# Horst Schaefer

I am trying to apply formal concepts from mathematics, logic or science in my work. One of my goals is to reach a balance between these formal aspects, artistic freedom and the resulting aesthetic appearance.

My previous submissions to Bridges consisted of variations of the classical tangram. A Tangram consists of seven pieces: a square, a parallelogram and 5 rectangular, isosceles triangles forming a square. My non-standard tangrams also consists of seven pieces. Every piece is either a square, a parallelogram or a rectangular, isosceles triangle but with different numbers for each piece. Putting them together, they fit into a square. Using these constraints I found 16 non-standard tangrams. One can identify them in the art work by searching for a square consisting of seven pieces.

With the classical tangram, one can create a square, a parallelogram and a rectangular, isosceles triangle. From the non-standard tangrams Nr 03, Nr. 04, Nr. 05, Nr.06, Nr.08, Nr. 09, Nr. 11 and Nr. 13 have this property. So one can use this property to apply a certain kind of recursiveness. The other non-standard tangrams cannot form either a parallelogram or a triangle or both. So they are only partially recursive.