Parallax Primes

Shaun Gilchrist and Nova Spivack have discovered an interesting way to look at prime numbers here. To see a larger image of it, I wrote the following javascript. Click the go button to run the code. packSize=100; // Number of integers per cell cellSize=5; // Number of pixels per cell function isPrime(n) { for(var i = 2, s = Math.sqrt(n); i <= s; i++) if(n % i === 0) return false; return n !== 1; } function packHasPrimes() { var myNum=curNum+x; for (var i=0;i<packSize;i++) { if (isPrime(myNum)) return 1; myNum+=y; } return 0; } function drawRow() { for (x=0;x<y;x++) { if (packHasPrimes()) ctx.fillStyle="#000000"; else ctx.fillStyle="#a00000"; ctx.fillRect (500+x*cellSize-y*cellSize/2,y*cellSize,cellSize+1,cellSize+1); } curNum+=packSize*y; y++; if (y<1000/cellSize) setTimeout("drawRow()",10); } curNum = 1; canvas = document.getElementById("canvas"); ctx = canvas.getContext("2d"); y = 1; drawRow();