The present invention relates to the field of magnetic assemblies, magnetic apparatuses and processes for producing optical effect layers (OEL) comprising magnetically oriented non-spherical magnetic or magnetizable pigment particles on a substrate and providing an impression of a crescent moon-shaped element moving or rotating upon tilting the optical effect layer (OEL). In particular, the present invention relates to magnetic assemblies, magnetic apparatuses and processes for producing said OELs as anti-counterfeit means on security documents or security articles or for decorative purposes.