Here's the code:
F=()=>{ c=v.getContext('2d') c.lineWidth=.03 C=[1,-.5,-.5] S=[0,.87,-.87] P=[[X=300,Y=300],[X,Y],[X,Y]] R=()=>{d=parseInt(Math.random()3) P=http://P.map (([x,y],i)=>(c.moveTo(x,y),c.lineTo(X=x+3C[I=(d+i)%3],Y=y+3*S[I]),[X,Y])) c.stroke() setTimeout(R,17) } R()}
Assumes no existing dependencies or dwitter-like shortcuts available. Needs this HTML to be on the page:
<canvas width=400 height=400 id="v"></canvas><script>F()</script>
Demo here: https://runkit.com/asyncanup/5cd629840a18bf001b4860e9
0|Math.random()*3
instead of parseInt(Math.random()*3) <body onload=F()>
before the canvas element, instead of having <script>F()</script>
after the canvas element