#let Y-SPACE = 10
#let PAR-SPACE = 10
#let COMMENT-PAD = 8
#let LIFELINE-W = 10

#let SYM-GAP = 5
#let PAR-PAD = (5pt, 3pt)
#let ACTOR-WIDTH = 20
#let BOUNDARY-HEIGHT = 20
#let CONTROL-HEIGHT = 20
#let ENTITY-HEIGHT = 20
#let DATABASE-WIDTH = 24
#let COLLECTIONS-PAD = (5pt, 3pt)
#let COLLECTIONS-DX = 3
#let COLLECTIONS-DY = 3
#let QUEUE-PAD = (5pt, 3pt)