While searching for ways to help my engineering students develop some desperately needed problem-solving stamina and spatial reasoning, I came across these wonderful puzzles that are in color – and provide solutions. (Did I mention I need to practice my spatial reasoning, too?)  I gave them the TED Ed River Crossing Riddle last week, and I thought I was about to have a full-on mutiny on my hands when I wouldn’t reveal the answer right away, so I thought I would try some less complex challenges for the next few weeks 🙂