Methods and apparatus implementing a technique for processing handwritten marks made on a machine-readable tablet. The technique includes providing multiple regions for input on the tablet; receiving from a user handwritten marks made in a current region of the plurality of regions; receiving from the user an indication that the current region is complete and thereupon selecting a different one of the plurality of regions as the current region in which to receive handwritten marks made by the user, whereby marks are received in a sequence of at least two regions; and representing the handwritten input as the aggregate of the marks written in the sequence of regions in a writing direction, the marks in different input regions having positions with respect to each other defined by a logical concatenation of the regions on the sequence of regions. The input can be arbitrarily-long markings of any kind.