diff --git a/docs/stirling.png b/docs/stirling.png
new file mode 100644
index 000000000..11695d86f
Binary files /dev/null and b/docs/stirling.png differ
diff --git a/docs/stirling.svg b/docs/stirling.svg
new file mode 100644
index 000000000..1a14a42f0
--- /dev/null
+++ b/docs/stirling.svg
@@ -0,0 +1,310 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   width="99.537987mm"
+   height="95.209366mm"
+   viewBox="0 0 99.537987 95.209366"
+   version="1.1"
+   id="svg745"
+   xml:space="preserve"
+   inkscape:version="1.2.1 (9c6d41e4, 2022-07-14)"
+   sodipodi:docname="stirling.svg"
+   inkscape:export-filename="stirling.png"
+   inkscape:export-xdpi="80"
+   inkscape:export-ydpi="80"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:xlink="http://www.w3.org/1999/xlink"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg"><sodipodi:namedview
+     id="namedview747"
+     pagecolor="#ffffff"
+     bordercolor="#666666"
+     borderopacity="1.0"
+     inkscape:showpageshadow="2"
+     inkscape:pageopacity="0.0"
+     inkscape:pagecheckerboard="0"
+     inkscape:deskcolor="#d1d1d1"
+     inkscape:document-units="mm"
+     showgrid="false"
+     inkscape:zoom="0.914906"
+     inkscape:cx="184.17193"
+     inkscape:cy="509.88845"
+     inkscape:window-width="2293"
+     inkscape:window-height="1387"
+     inkscape:window-x="122"
+     inkscape:window-y="25"
+     inkscape:window-maximized="0"
+     inkscape:current-layer="svg745" /><defs
+     id="defs742"><linearGradient
+       inkscape:collect="always"
+       id="linearGradient72198"><stop
+         style="stop-color:#ccd6d7;stop-opacity:1;"
+         offset="0"
+         id="stop72194" /><stop
+         style="stop-color:#0f3a3f;stop-opacity:1;"
+         offset="1"
+         id="stop72196" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient71928"><stop
+         style="stop-color:#4b0005;stop-opacity:1;"
+         offset="0"
+         id="stop71924" /><stop
+         style="stop-color:#8f000c;stop-opacity:1;"
+         offset="1"
+         id="stop71926" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient71920"><stop
+         style="stop-color:#4b0005;stop-opacity:1;"
+         offset="0"
+         id="stop71916" /><stop
+         style="stop-color:#8f000c;stop-opacity:1;"
+         offset="1"
+         id="stop71918" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient69598"><stop
+         style="stop-color:#6a0007;stop-opacity:1;"
+         offset="0"
+         id="stop69594" /><stop
+         style="stop-color:#b8000f;stop-opacity:1;"
+         offset="1"
+         id="stop69596" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient46361"><stop
+         style="stop-color:#f7f6f8;stop-opacity:1;"
+         offset="0"
+         id="stop46359" /><stop
+         style="stop-color:#b7b7b5;stop-opacity:1;"
+         offset="1"
+         id="stop46357" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient40554"><stop
+         style="stop-color:#f4f2f4;stop-opacity:1;"
+         offset="0"
+         id="stop40550" /><stop
+         style="stop-color:#57767b;stop-opacity:1;"
+         offset="1"
+         id="stop40552" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient39095"><stop
+         style="stop-color:#285459;stop-opacity:1;"
+         offset="0"
+         id="stop39093" /><stop
+         style="stop-color:#a6b6af;stop-opacity:1;"
+         offset="1"
+         id="stop39091" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient36672"><stop
+         style="stop-color:#da453f;stop-opacity:1;"
+         offset="0"
+         id="stop36668" /><stop
+         style="stop-color:#a60008;stop-opacity:1;"
+         offset="1"
+         id="stop36670" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient19524"><stop
+         style="stop-color:#3a4b4f;stop-opacity:1;"
+         offset="0"
+         id="stop19522" /><stop
+         style="stop-color:#617979;stop-opacity:0.97461927;"
+         offset="1"
+         id="stop19520" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient17996"><stop
+         style="stop-color:#401016;stop-opacity:1;"
+         offset="0"
+         id="stop17994" /><stop
+         style="stop-color:#761f19;stop-opacity:1;"
+         offset="1"
+         id="stop17992" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient15569"><stop
+         style="stop-color:#8ea8ad;stop-opacity:1;"
+         offset="0"
+         id="stop15565" /><stop
+         style="stop-color:#e9e7eb;stop-opacity:1;"
+         offset="1"
+         id="stop15567" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       id="linearGradient15557"><stop
+         style="stop-color:#9b0e11;stop-opacity:1;"
+         offset="0"
+         id="stop15553" /><stop
+         style="stop-color:#370707;stop-opacity:1;"
+         offset="1"
+         id="stop15555" /></linearGradient><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient15557"
+       id="linearGradient15559"
+       x1="120.06672"
+       y1="63.25761"
+       x2="135.16347"
+       y2="78.078682"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient15569"
+       id="linearGradient15571"
+       x1="127.97037"
+       y1="101.66144"
+       x2="133.88971"
+       y2="104.77026"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient17996"
+       id="linearGradient17998"
+       x1="117.9284"
+       y1="86.055084"
+       x2="130.67392"
+       y2="76.945541"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient19524"
+       id="linearGradient19528"
+       x1="130.98172"
+       y1="82.402977"
+       x2="135.72115"
+       y2="86.45166"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient36672"
+       id="linearGradient36674"
+       x1="63.797714"
+       y1="74.81752"
+       x2="96.636673"
+       y2="120.29293"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient39095"
+       id="linearGradient39097"
+       x1="120.54506"
+       y1="124.76902"
+       x2="128.04152"
+       y2="126.0704"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient40554"
+       id="linearGradient40556"
+       x1="113.84585"
+       y1="114.04285"
+       x2="119.65858"
+       y2="128.50244"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient46361"
+       id="linearGradient46363"
+       x1="73.993439"
+       y1="114.13906"
+       x2="94.845322"
+       y2="71.247383"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient69598"
+       id="linearGradient69600"
+       x1="95.854446"
+       y1="114.66749"
+       x2="103.77842"
+       y2="120.1887"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient71920"
+       id="linearGradient71922"
+       x1="98.580376"
+       y1="87.186958"
+       x2="118.09738"
+       y2="101.19449"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient71928"
+       id="linearGradient71930"
+       x1="78.278267"
+       y1="97.433273"
+       x2="92.313202"
+       y2="104.33479"
+       gradientUnits="userSpaceOnUse" /><linearGradient
+       inkscape:collect="always"
+       xlink:href="#linearGradient72198"
+       id="linearGradient72200"
+       x1="125.76636"
+       y1="138.46817"
+       x2="123.3327"
+       y2="126.03291"
+       gradientUnits="userSpaceOnUse" /></defs><g
+     inkscape:groupmode="layer"
+     id="layer4"
+     inkscape:label="background"
+     style="display:inline"
+     sodipodi:insensitive="true"
+     transform="translate(-51.420144,-44.470286)"><rect
+       style="display:inline;fill:#ccd6d7;fill-opacity:1;stroke:none;stroke-width:4.13755;stroke-linecap:round;stroke-linejoin:round;stroke-miterlimit:3.2"
+       id="rect72067"
+       width="99.481979"
+       height="94.999512"
+       x="51.476147"
+       y="44.680138" /></g><g
+     inkscape:groupmode="layer"
+     id="layer5"
+     inkscape:label="shadow"
+     style="display:inline"
+     sodipodi:insensitive="true"
+     transform="translate(-51.420144,-44.470286)"><path
+       style="display:inline;fill:url(#linearGradient72200);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 84.146049,134.73858 c 0,0 11.721038,2.48294 17.938661,2.91673 6.21763,0.43378 14.75251,0.59994 22.41237,-0.43379 8.01008,-1.081 13.19907,-2.22733 14.50043,-2.66112 1.30136,-0.43379 4.00784,-1.24297 4.15244,-2.25514 0.1446,-1.01217 -3.4703,-2.74733 -6.21763,-3.32571 -2.74732,-0.57838 -12.72444,-1.44596 -14.89337,-1.44596 -2.16894,0 -37.892901,7.20499 -37.892901,7.20499 z"
+       id="path72192"
+       sodipodi:nodetypes="cssssssc" /></g><g
+     inkscape:groupmode="layer"
+     id="layer2"
+     inkscape:label="Origami"
+     style="display:inline"
+     sodipodi:insensitive="true"
+     transform="translate(-51.420144,-44.470286)"><path
+       style="display:inline;fill:url(#linearGradient40556);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 84.460552,134.86721 35.165798,-6.85679 16.15467,-42.7383 z"
+       id="path960"
+       sodipodi:nodetypes="cccc" /><path
+       style="fill:url(#linearGradient15571);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 135.71493,85.428056 0.3984,45.049024 -9.66213,-20.46173 z"
+       id="path964"
+       sodipodi:nodetypes="cccc" /><path
+       style="display:inline;fill:url(#linearGradient39097);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 119.60518,128.00293 16.5337,2.48693 -9.68769,-20.5512 z"
+       id="path966"
+       sodipodi:nodetypes="cccc" /><path
+       style="display:inline;fill:url(#linearGradient15559);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 118.42209,57.022622 12.70423,-2.766809 -0.0785,25.087175 -12.43878,-13.376518 z"
+       id="path968"
+       sodipodi:nodetypes="ccccc" /><path
+       style="display:inline;fill:url(#linearGradient19528);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 135.72114,85.386768 -4.84219,-6.459493 0.0305,11.126604 z"
+       id="path970"
+       sodipodi:nodetypes="cccc" /><path
+       style="display:inline;fill:url(#linearGradient17998);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 119.10273,65.682415 11.96883,13.44935 -0.0899,10.819868 -11.88577,11.430427 z"
+       id="path972"
+       sodipodi:nodetypes="ccccc" /><path
+       style="display:inline;fill:url(#linearGradient36674);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="M 62.145635,130.15618 62.043392,65.435258 c 0,0 0.179321,-2.778132 1.89516,-4.036097 1.874923,-1.374597 4.341768,-1.894096 4.341768,-1.894096 l 50.91788,-11.349167 -0.0113,53.144272 -34.733274,33.56547 z"
+       id="path958"
+       sodipodi:nodetypes="ccsccccc" /></g><g
+     inkscape:groupmode="layer"
+     id="layer3"
+     inkscape:label="Letter"
+     style="display:inline"
+     sodipodi:insensitive="true"
+     transform="translate(-51.420144,-44.470286)"><path
+       style="display:inline;fill:url(#linearGradient69600);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 94.780881,91.406803 16.870379,17.074877 -23.723345,23.00249 -18.122131,-17.99816 5.497473,-2.80607 18.404054,-0.0511 2.35163,-8.23071 z"
+       id="path54894"
+       sodipodi:nodetypes="cccccccc" /><path
+       style="display:inline;fill:url(#linearGradient71930);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 72.440405,92.224764 16.15467,15.745686 4.089788,-6.79927 z"
+       id="path54892" /><path
+       style="display:inline;fill:url(#linearGradient71922);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 95.138739,84.965385 1.124691,-14.109776 22.92453,22.286787 0.008,8.164604 -3.28863,3.16649 z"
+       id="path54890"
+       sodipodi:nodetypes="cccccc"
+       inkscape:label="path54890" /><path
+       style="display:inline;fill:url(#linearGradient46363);fill-opacity:1;stroke:none;stroke-width:0.264583px;stroke-linecap:butt;stroke-linejoin:miter;stroke-opacity:1"
+       d="m 95.138739,84.965385 h 1.226936 l -0.05112,-14.109776 c 0,0 -5.776827,-3.220709 -12.167126,-2.40275 -6.390296,0.817957 -8.151582,2.1248 -10.58233,4.396523 -1.90229,1.777838 -2.913974,3.527446 -3.987546,7.157132 -0.512646,1.733226 -0.281963,5.988892 0.613471,8.537436 0.664591,1.891528 2.453873,4.294281 4.958868,6.134686 2.662335,1.956002 8.281825,3.527443 8.281825,3.527443 0,0 5.134614,1.887351 5.572338,4.294281 0.308137,1.69437 -0.102243,3.22071 -1.635914,4.95887 -1.258314,1.42609 -3.62969,1.99377 -6.288054,1.07357 -2.658364,-0.92021 -6.139514,-3.85065 -7.106009,-4.90775 -0.817958,-0.89464 -2.820665,-3.06173 -2.890231,-4.294021 -0.01209,-0.214205 -1.229505,-0.0963 -1.229505,-0.0963 l -0.0723,14.256941 5.879073,2.24938 c 0,0 5.214483,1.78929 8.946415,1.43143 3.731934,-0.35786 7.617235,-0.51122 11.604778,-5.16336 3.987542,-4.65213 3.680812,-12.831715 2.147141,-15.899056 -1.533673,-3.067344 -3.561212,-6.138812 -10.480087,-8.281826 -5.776829,-1.789283 -7.872846,-3.01622 -8.128458,-4.396524 -0.255611,-1.380305 0.0091,-4.253646 2.760607,-5.214481 3.220711,-1.124693 5.623462,-0.05112 7.05489,1.12469 1.431425,1.175817 5.572339,5.623462 5.572339,5.623462 z"
+       id="path46355"
+       sodipodi:nodetypes="cccssssscssssscccssssssscc" /></g></svg>