A sheet creasing device (1) is operable to form folding guide creases (8, 9, 10) in a sheet (7) to facilitate folding the sheet (7) to form a weaving element. The device (1) has a base support (2) on which is mounted a paper creasing assembly (3) operable to impress a number of fold lines (8, 9, 10) in a paper sheet (7) delivered between complementary rollers in the creasing assembly (3). A top portion (4) of the device (1) is adapted for manually pressing downwardly to clamp the device (1) against a support surface such as a table whilst winding a handle (19) of the creasing assembly (3) to feed the sheet (7) between the creasing rollers.