I think any song by Alt-J would be extremely hard to cover, because their technique and style is so unique. But Mumford and Sons does a great job turning this sultry song into a raw, acoustic dream.
Mumford and Sons - Tessellate
Ellie Goulding also does an awesome job covering this song! Check it out.
Also, here's a math lesson for you! What is tessellating?
The process of creating a two-dimensional plane using the repetition of a geometric shape with no overlaps and no gaps. (Thanks, Wikipedia!)
M.C. Escher was a huge influence on making tessellation patterns into art. Here is some of his artwork: