Have a look at this. http://therion.speleo.sk/wiki/doku.php/metapost You will find a symbol which I defined for a stalagmite boss which I guess is what you are talking about. def p_u_boss (expr pos,theta,sc,al)= T:=identity aligned al rotated theta scaled sc shifted pos; pickup PenD; p := (0.08u,0.25u)..(0,0.29u)..(-0.08u,0.25u); q := (0.16u,0.5u)..(0u,0.58u)..(-0.16u,0.5u); for i=0 upto 9: thdraw p rotated 36i; thdraw q rotated 36i; endfor p := fullcircle scaled 0.15u; thdraw p; enddef; To use a user defined symbol click on type U in the points drop down and then after the U, type in a colon followed by the name of your symbol so, in the case of the above "U:boss" Dave Clucas daveclucas.com mycaves.org. daveclucas@icloud.com