in web/src/drawing.js [178:191]
function drawPaths(ctx, size, paths) {
for (var i = 0; i < paths.length; ++i) {
var path = paths[i];
if (path.length < 2) {
path = [path[0], [path[0][0] + 0.001, path[0][1] + 0.001]];
}
ctx.beginPath();
ctx.moveTo(path[0][0] * size, path[0][1] * size);
for (var j = 1; j < path.length; ++j) {
ctx.lineTo(path[j][0] * size, path[j][1] * size);
}
ctx.stroke();
}
}