Abstract: A random pattern generator is used to generate waveforms displayed on a cathode ray tube. A plurality of waveforms are built up to form an observed pattern for use in the design of textiles or carpets. To form a waveform a series of numbers Xi (i=1, 2, 3 . . . ) are generated each representing an amplitude value of a waveform X. Each value of Xi is translated into a number Y in a series of numbers Z, then incremented by a changeable amount A to obtain a different value Zi which collectively are used to trace out a pattern on the cathode ray tube. The observed pattern changes with each value of A. Generation of Xi and Zi may be from programmed read only memories. The series Zi may be a pseudo random sequence of numbers.