Revert "some tests for didactic"

This reverts commit 012eccf6488739c3c3528394481511e5c1d517b2.
Revert "example projects"

This reverts commit 38007d8fa1e477fc8e482e46bd6fc256d7a845be.
Revert "first testStubs chessboard"

This reverts commit 5b595d44e2b440747dd71d239f477de5274cdfd0.
revert to clean project