With "alg_pknot_shapes.gap" we carry over the idea of shape abstraction to pseudoknots. We define the same five levels of abstraction, but the shape strings will have a slightly different look. To retain the crossing stem indication by special types of brackets, we now use normal parentheses ( ) for nested sub-structures, square brackets [ ] for alpha helices, curly brackets { } for beta helices and angle brackets < > for gamma helices of pseudoknots. You will find the five "normal" algebras plus a unifying alg_pknot_shapeX version.