Rapid Prototyping

Today in class we did an exercise where we had to come up with a game based on a word chosen from a list. Our group picked the word 'round'. I found that this criteria was helpful in generating many ideas for games with the theme of 'round' but not all of them seemed plausible. What I'm trying to say is that this exercise is a good way to generate many ideas, but as a team, we should not rely solely on this method. We should use it in conjunction with other methods of creativity. Maybe do several brainstorming sessions with different words, I'm not sure, but it just seems that this method narrows creativity. What other ways are there to unleash our creative minds in designing games.