Edge template IV2a

The edge template IV-2-a
R4 C4 Vc1 Vd1 Sa1 Sa2 Sa3 Sb1

Red has two relevant threats: R4 C4 Vc1 Vd1 Vb3 Pb2 Pc2 Pa4 Pb4 Sa1 Sa2 Sa3 Sb1 and R4 C4 Vc1 Vd1 Vc3 Pc2 Pd2 Pb4 Pc4 Sa1 Sa2 Sa3 Sb1

This leaves blue with two options:

R4 C4 Vc1 Vd1 Pc2 Pb4 Sa1 Sa2 Sa3 Sb1

Solution to the intrusion at c2
R4 C4 Vc1 Vd1 H1c2 V2d2 H3c4 V4b3 Sa1 Sa2 Sa3 Sb1 The b3 piece is connected to the bottom and connects to the top via either b2 or c3.

Solution to the intrusion at b4
R4 C4 Vc1 Vd1 H1b4 V2d3 H3d2 V4b3 Sa1 Sa2 Sa3 Sb1 The b3 piece connects via either a4 or c3.