I'm loving abusing this! The only problem is there are too many people trying their scripts at the same time, but it's really cool you left it completely hackable!
for (i=0;i<60;i++) { for (j=0;j<60;j++) { firebaseCanvasData.child(i+':'+j).set("rgb("+(255-i*2)+","+(255-j)+","+(i*j)+")") }}
Edit: Ok, definitely too many people abusing it...