How high can you piss up a wall?

I have been in this house for seventeen years. My second son, Jed, was born a few months after moving in. This is our inbuilt height chart. The marks are ground into the wood with ball-point pen. I stopped letting the kids record me when they noticed a slight decrease in height – uh uhh I worked hard to get to my lofty 5’ 5 1/2”.
Jed has just topped 6” and is inordinately proud of it. So much so that he wound some insulation tape around the beam, and called it ‘The Jed Line’. I found this quite funny. Jed’s stepfather did not and was annoyed by it. He tops six foot too, so it wasn’t an inferiority thing. He thought it might ‘damage the wood’ and ‘make it hard to paint’. We all burst into hysterical laughter at this statement, seeing that it is ruined already and it NEVER gets painted. He was not amused.Jed, being the most amenable member of this family, asks Seán if he wants him to take it down - this after me arguing for 5 minutes (on his behalf) that it should stay. Seán say 'Yes please' and Jed calmly unwinds it and puts in in the bin. This boy should join the UN.