In a method for the production of a facetted mirror 24 having a plurality of mirror facets 12 and 12\u2032, which have mirror surfaces 15 and are fitted into reception bores 22, 22\u2032 of a support plate 16, the mirror facets 12, 12\u2032 are made in a first method step. The circuit includes a duplicate transconductor element for duplicating AC current in a transconductor pair of the double-balanced mixer circuit. That is, a node which is in contact with an external power supply and thus requires a high breakdown voltage is formed of a thick gate oxide film transistor, while a node which is not in contact with the external power supply is formed of a thin gate oxide film transistor. The module can be tilted there so that no air bubble, which prevents complete filling, can form below the concavely curved optical surface. Slab drop-forms starting at the roof and progressing floor-by-floor downward allow monolithic post-tensioned floor slabs to be cast to tie the skeleton into a unitary structure. A clutch linkage can include a control shaft pivotable about an axis, a substantially U-shaped arm connected at two points to the shaft, and a plurality of projections positioned on the arm.