Leave your mark in Amsterdam

Holy shit, we should decide on some place in amsterdam where when a RIU member goes there they leave their name/mark so that we have like a little memorial for all those who made the trip there. Ill be there next week, either somebody knows some place where you could etch in a name or ill scope it out then and give everybody directions how to find the spot. What do you all think?

I would totally leave my mark its probably gonna be another year to 3 years before I head out that way but eventually I wanna go for the
Cannabis CuP