At the moment all the blocks have the same theme. But i'll move onto fixing that next.
But as you can see below it is possible to have a gradient colour scheme for your blocks. You can define it however you want
if you want to get really wacky you can look into radial gradients, have as many colours as you want. (please don't actually put something like this in production though)
to do this i modified the line referenced by Beka
to this.
this.svgPath.setAttribute('style', "fill:url(#lgrad)");
where lgrad is defined earlier as i described above.
I'm not sure if this in the end is going to make any improvement. It may make it very difficult to see whats going on. That second one demonstrates one potential drawback of something like this.
But yeah. If someone sees this and finds an awesome theme i'd love to see it! I'm going to be playing around for a bit now and if i come up with something nice i will share it.