An apparatus comprising: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform: determining at least one parameter dependent upon a user gesture wherein the parameter is rotation invariant, having the same value when determined at different arbitrary orientations between the apparatus and the user gesture; and using the at least one parameter to determine an action in response to the user gesture.