With regard to the pink triangles, that is correct. The Nazi's had a whole system of coloured symbols to classify their concentration camp prisoners. In addition to the well known "yellow star of david" used for Jewish prisoners and the "pink triangle" for homosexuals, there was a black square I believe was for "political prisoners" and as well as one for Gypsies/Roma that I can't remember offhand.
Apart from the "Star of David" shape chosen to represent Jews, and perhaps the pink colour chosen to represent homosexuals, there is no other overt symbolism in the choice of symbols - they are rather simple colours and shapes.
Apart from the "Star of David" shape chosen to represent Jews, and perhaps the pink colour chosen to represent homosexuals, there is no other overt symbolism in the choice of symbols - they are rather simple colours and shapes.