< > Our ability to visualize things begins and ends in three dimensions, even if we refer to point particles for convenience. (The physicist Richard Feynman once said that thinking of a subatomic particle as a little ball has not been valid since 1910.) [84] When we imagine point particles we cannot help but to decorate them with 3-D highlights, a bottom and a top and other inappropriate 3-D attributes. Never mind trying to imagine 5-D objects--we can't even imagine 2-D or 1-D objects in anything other than three dimensions!