The -v option with six numbers matches three vertices on
the brick (second set of three index numbers) with three on the base
(first set of three index numbers) by a translation to align
the first pair of vertices, then a rotation to align the second pair,
then a rotation about the line joining these two vertices to align
the third pair of vertices.
In this example a square pyramid has three verices on its face aligned
with those of an ictagonal pyramid. Notice that the base polyhedron in
the off_align command is read from standard input.
View this model with the command
polygon pyr 8 | off_trans -R 0,0,10 -R 110,0,0 | off_align -v pyr4,0,2,3,2,1,0 -M 2 | antiview