Maybe we can use an approach that Thomas Holder demonstrated here https://therion.speleo.sk/wiki/metapost#scale_dependant_visualization_of_sym... def l_rockborder (expr p) = if abs(llcorner p - urcorner p) > u: l_rockborder_UIS(p); fi; enddef; Simply enclosing an existing metapost definition within a user customised metapost wrapper. In the case above, it is "if the symbol is big enough, draw it". What we want instead is, "draw the symbol, draw a box around it". I expect something like bbox should enable us to put a line around a symbol, regardless of whether it is a text or arbitrary linework. I'll leave it to someone else to explore... Bruce -----Original Message----- From: Therion <therion-bounces@speleo.sk> On Behalf Of Andrew Atkinson via Therion Sent: Friday, 21 September 2018 09:16 To: therion@speleo.sk Cc: Andrew Atkinson <andrew@wotcc.org.uk> Subject: Re: [Therion] Height numbers in square boxes ... Yes I'm having similar problems to you defining a box, my skills are generally limited to copying existing definitions and adjusting them slightly. My guess is that it is not a metapost, it is tex as it is a label, in tex you can put a box round text with \fbox{4} but how or if you can use that in therion I do not know. It is a problem that is interesting me, as I think it is something that I might want to use. Andrew