petrik, It depends on the type of block. When I'm stuck for an idea about something to model I'll just pick a random item somewhere in the house & try to recreate it. If I'm stuck on an ongoing project I usually just harness up the cat, let him take me for a walk (I live next door to a park), & try to keep him from terrorizing the dogs. After an hour or so of that I'm ready to attack the problem with a new perspective