Welp, that took up a chunk of my day. This is as far as I got tricking it into doing webgl (it just renders a triangle):
if(!window.g){gc=document.createElement('canvas');g=gc.getContext('webgl');c.parentNode.replaceChild(gc,c);k=Object.keys(g.__proto__);d='void main(){gl_';str = `g395(g41,g318())g310(g41,new Float32Array([0,0.5,0,-0.5,-0.5,0,0.5,-0.5,0]),g46);a=g322(g139)g382(a,'attribute vec3 c;${d}Position=vec4(c,1);}')g313(a);b=g322(g138)g382(b,'${d}FragColor=vec4(1,0,1,0);}')g313(b);d=g320()g302(d,a)g302(d,b)g376(d)g393(d)g435(0,3,g128,0,0,0)g406(0)g404(g12,0,3)`.replace(/g(\d+)/g,"\ng.\${k[$1]}");eval("eval(`"+str+"`)")}
I assume there are far more advanced methods than what I managed to do, so it's probably possible to actually get that to 140 characters.
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