of the pattern cams 10 is reduced to 1 8 of the rotation speed of the drive shaft 8 and the rotation speed of the pattern cams 28 is reduced to 1 36 of the rotation speed of the drive shaft 8 a pattern such as a crescent pattern actually obtained may be of a smaller size with a length l 1 by way of example as shown in fig4 in case the corresponding pattern cam is selected from the group of pattern cams 10 on the other hand the same crescent pattern actually obtained may be elongated twice to the size with a length l 2 by way of example as shown in fig5 in case the corresponding pattern cam is selected from the group of pattern cams 28 the speed reduction of pattern cams 10 28 may be optionally varied according to the second embodiment of the invention when the worm gear 11 is rotated the pattern cams 10 are rotated together with the worm gear 11 and the rotation of the worm gear 11 is transmitted to the pattern cams 40 through the series of gears 39 44 41 the rotation speed of the pattern cams 10 and 40 may be.