Ideas:

1. When I started school at the age of seven I was given a wooden ruler which I still vividly can remember, with red and black markings showing lengths in decimeters and centimeters. Because of that I would like to call the rectangular type of sign to the left above for 'ruler', which for me means three things: a. Made of wood. b. Decides (i.e. rules) over things (e.g. short, medium or long). c. Carries force (a whack on the fingers if you don't behave).

2. Possibly the variant of 'ruler' which stands not on a horizontal short end but on a downward sloping one (Monday and Friday) is an indication of the female sex.

Sunday, Tuesday, Wednesday, Thursday and Saturday then would be male.