Brainstorming (Creative Thinking Warm-up Exercise)

Just a quick reflection on work related stuff. After reading the six stages on how to conduct a brainstorming session as proposed by Downe (2005). 
Brainstorming sessions at my previous workplace consisted of the manager giving a short briefing on the problem's background and what needed to be done. It would be then followed by a few rules in which we were told to throw out as many solutions as possible, encouraged to come up with creative ideas and strongly reminded not to criticize others' opinion.

Before we began, the manager did a short warm session to prepare ourselves to be creative. He asked us questions like, "How many ways can we draw a triangle?" and "What time was it 8 hours ago?". Then he gave us a 30-minute period for the brainstorming session to be conducted. As the session began, he started jotting down everyone's ideas. This was followed by the end of the session and our manager collected all the necessary information and thanked everyone for their absolute participation.