This is one of the designs described by Ferdinand Lammertink in 1996 in 'polyshapes'.
A Butterfly made from the complete set of 35 hexominoes, in a tray measuring 19 x 13 cm..
Very few copies were produced by George Miller in 2003, this is one of them.
It is still in original shrink wrapping, ready for the first puzzler who dares to scramble and solve it.
The design is mentioned and shown (along with the butterfly/hexominoes and pentahexes) by George on his website as part of a set: www.puzzlepalace.com/#/puzzles/200417
George also wrote about this specific puzzle:
The Butterfly Puzzle is taken from Ferdinand Lammertink's unpublished book, 'Polyshapes, Part 1'. It is a beautiful arrangement of the 35 hexaminoes. The hexaminoes represent all the different ways six squares can be glued together side to side. The puzzle is made from a phosphorescent acrylic while the tray is presented in a phosphorescent acrylic of a contrasting color and a backing of blue acrylic.
Naturally there are thousands of ways these 35 pieces can fit in the tray. The bottom of the tray has 29 squares etched into the plastic to give a visual clue as to what squares must be avoided to come up with the final symmetric pattern.