Edit in JSFiddle

Result
JavaScript

var draw = SVG('drawing').size(500, 130)

var pattern = draw.pattern(20, 20, function(add) {
  add.rect(20,20).fill('#f06')
  add.rect(10,10).fill('#0f9')
  add.rect(10,10).move(10,10).fill('#fff')
})

draw.rect(100, 100).move(20, 20).radius(10).fill(pattern)