Chaos tiles

Many interesting information about this type of pieces you can find at these pages (by Ed Pegg Jr )
http://www.mathpuzzle.com/chaotile.html
http://www.mathpuzzle.com/convex.html

New:

2

9

9

14
  

18

22 (18+4k)

30  (18+4k)

Very interesting "crystal-like" structure