As an example : the following patch allows to associate an icon to a (small, without content) rectangle
@startuml
sprite $businessProcess [16x16/16] {
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFF0FFFFF
FFFFFFFFFF00FFFF
FF00000000000FFF
FF000000000000FF
FF00000000000FFF
FFFFFFFFFF00FFFF
FFFFFFFFFF0FFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFF
}
rectangle "business process" <<$businessProcess>>
@enduml
==== Patch URL : this patch needs the right alignement patch to be applied (http://plantuml.sourceforge.net/qa/?qa=4075/vertical-blocks-right-aligned-stereotype-title-component) ==
https://filex.univ-jfc.fr/get?auto=1&k=rquQcDgLlQ6yU8zKMPD