// Constructor
public VisualWallParts(VisualMiddleSingle m)
{
this.upper = null;
this.lower = null;
this.middledouble = null;
this.middlesingle = m;
}
// Constructor
public VisualWallParts(VisualUpper u, VisualLower l, VisualMiddleDouble m)
{
this.upper = u;
this.lower = l;
this.middledouble = m;
this.middlesingle = null;
}