revealed that power law distributions arise in fragmentation phenomena due to an underlying phase transition [@instable; @transition; @univer]. However, most of the data reported in the literature is concerned with the general behavior of fragmentation processes. There is much less literature where the propagation and orientation of cracks are discussed.

In the present paper we study the normal and oblique impact of a circular brittle particle on a hard frictionless plate, varying the impact velocity and impact angle in a broad range. The particle is composed of numerous unbreakable, undeformable, randomly shaped polygons which are bonded together by elastic beams. The bonds between the polygons can be broken according to a physical breaking rule, which takes into account the stretching and bending of the connections. Based on simulations of the model, we performed a detailed study of the failure evolution at different impact velocities and of the nature of the crack propagation during the fragmentation process, and compared the results with experiments [@fra_pattern; @powder; @lab; @ice; @fra_glass]. In the analysis of the simulation data, we profit from recent theoretical results of general studies of fragmentation processes. We observed that for both normal and oblique impacts, the crack patterns are the 