NOT.8:5.2 - Read a movement relative to a changing body frame

A tabletop movement score uses two signs. R means move one grid unit to the performer’s right without turning; F(2) means move two units forward without turning. The signs describe successive completed displacements. The starting position is (0, 0), with east as positive x and north as positive y.

A performer initially facing north reads R; F(2) as an eastward unit displacement followed by two northward units. The endpoint is (1, 2). The reading procedure first recovers the starting orientation, translates each body-relative direction into the grid frame, updates the position and continues from there.

Now the performer starts facing east. The same score yields one unit south and two units east, ending at (2, -1). Treating R as page-right would give a different route. If the intended task is to preserve the original grid-space path regardless of orientation, choose a grid-relative notation or construct the appropriate body-relative instructions; keeping the marks unchanged does not meet that new task.

The score leaves the speed and path within each displacement unspecified. It can guide a prepared person moving a token. Making a physical robot perform it additionally requires an applicable motion method and an account of its realization. Reading the endpoint establishes neither that method nor a performed movement.