These were a trend back in the mid 70s. They were pretty self-explanatory really,- seven pairs of pants, each with a day of the week on them, and either a cartoon or floral motif or something. You could anyone's personality by the wearing of these undergarments. If they were the sensible and fastidious type, they'd always match the correct pair for that day. If they were a bit of an anarchist, they'd think nothing of wearing Saturday's pants on a Monday and behaving accordingly! Crazy stuff!