Gyrochoron

A gyrochoron, also known as a step tegum, is an isochoric polychoron formed as the dual to the step prism.

Examples
5-2: Pentachoron

6-2: Triangular duoprism

7-2 and 7-3: 7-2 gyrochoron

8-2: 8-2 gyrochoron

8-3: Tesseract

9-2 and 9-4: 9-2 gyrochoron

9-3: 9-3 gyrochoron

10-2: 10-2 gyrochoron

10-3: Decachoron

10-4: Pentagonal duoprism

11-2 and 11-5: 11-2 gyrochoron

11-3 and 11-4: 11-3 gyrochoron

12-2: 12-2 gyrochoron

12-3: 12-3 gyrochoron

12-4 12-4 gyrochoron

12-5: Hexagonal duoprism

13-2 and 13-6: 13-2 gyrochoron

13-3 and 13-4: 13-3 gyrochoron

13-5: 13-5 gyrochoron