gap> tub:=ArcDiagramToTubularSurface(arc);        
Map of regular CW-complexes

gap> tub:=ArcDiagramToTubularSurface([arc,cross]);
Map of regular CW-complexes

gap> tub:=ArcDiagramToTubularSurface([arc,cross,cols]);
Map of regular CW-complexes

gap> List([1..Length(Source(tub)!.boundaries[3])],x->tub!.colour(2,tub!.mapping(2,x)));
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