If 72% of the people have had ideas or breakthroughs in the shower and 17% of the people feel inspired while showering, you shouldn't install a shower in the office to increase creative problem-solving. You should make sure there is time to "not think" about the problem and let the mind settle.
When you have a problem, and you focus hard on finding a solution, you’re stressed out, it’s super important, run against a deadline, management is breathing down your neck, clients are calling,… how often did you find the solution?