There are: Black Nights in a6 and g5, black pawns in c5,c3,e3 and h6; white pawns in d7 and g3, white King in d6, White Bishop in d2, white Night in g4.
Story:
It was first seen it when British GM Jim Plaskett who presented it at the tournament in Brussels 1987 (Kasparov and Ljubomir won with 8.5/11, Karpov was second with 7/11). None of the grandmasters at the tournament could solve it, except for Michail Tal who looked at it for a few minutes and went for a walk in the park. He came back with the solution.
Have fun
