polyiamonds and rotational symmetry

a hexiamond is made with 6 equilateral triangles stuck together, edge to edge

find all 12 of the hexiamonds

or use these:

(these are given names in some sources)
















put two of the same hexiamond shapes together to create a shape with rotational symmetry

explore other options

or use these resources:

try to fit all 12 hexiamonds together to fill this shape

one solution

there are others....

55 altogether according to
David Goodger












thanks to recmath for these ideas and further information