Tessellations are the coolest — a figure interlocks with itself perfectly to fill the page, with no overlaps or gaps. I created the website Tiled.art to explore their many delights.
Here are some nice examples (click to open a full view on the site):
On the site you can also learn about the symmetries behind the art.
And you can create your own tessellation, with the shapes staying interlocked automatically. Here are a few of mine, created on the site (click for a full view):
Tiled.art is a free site, with no ads. I hope you enjoy it!
And for a quick preview check out this video.