Offset tile pattern “Tile6zz” and the resulting inhomogeneous sky coverage for co-added data products. The labeled panels show the consecutive construction of a tile from a series of six telescope offset positions. In each of these panels, the red boxes mark the current coverage of the VIRCAM pawprint, which is shown in gray in the subsequent offset steps. The two panels on the right show the effect of this observation strategy on the effective exposure time and the relative observing time for a typical observation block in the VISIONS program.