Disclosed is a patterning device for patterning product structures onto a substrate and an associated substrate patterned using such a patterning device. The patterning device comprises target patterning elements for patterning at least one target from which a parameter of interest can be inferred. The target patterning elements and product patterning elements for patterning the product structures. The target patterning elements and product patterning elements are configured such that said at least one target has at least one boundary which is neither parallel nor perpendicular with respect to said product structures on said substrate.