Nr. 412
Model of a periodic surface (Minimal surface ?)
Row: 1

Nr. 375
Plane (almost mathematical) pendulum
Row: 1

Nr. 259
Triple connected Riemann surface
Row: 2

Nr. 258
Windings point of 2. order on a Riemann surface
Row: 2

Nr. 257
Windings point of 1. order on a Riemann surface
Row: 2

Nr. 924
Four-leaved Riemann surface
Row: 3

Nr. 863
Riemann surfaces
Row: 3

Nr. 863
Riemann surfaces
Row: 3

Nr. 942
Digital solar clock
Row: 4