small bathrooms. i have kind of a similar fear, but I'm really only scared of small bathrooms, or monochromatic ones or ones with labels and directions as to what to do (like airplane or cruise ship bathrooms) I hate flying because of my fear, and always avoid airplane bathrooms.
A rectangular prism is solid 3-dimensional object which has six  faces that are rectangles. It has 12 edges and 8 vertices.
There are nine edges on a triangular prism to answer your question.9 There are 9 edges, 6 vertices and 5 faces on a triangular prism.