laps – Zero-width boxes for an­no­ta­tions, etc

Pro­vides macros ex­tends the \llap/\rlap set in Plain TeX: – \ulap and /dlap are up and down laps, in the same se­ries as the orig­i­nals; – \xlap and \ylap are laps in the hor­i­zon­tal and ver­ti­cal di­rec­tions, re­spec­tively, and – \zlap pro­vides a box of zero di­men­sions in both axes, cen­tred on its mid­point.