Slide showing squared table with each square numbered and labelled with several variations of the term RRSSTT. Slide shows squared table with each square numbered and labelled with several variations of the term RRSSTT. Squares are numbered from 1 - 64. In each box there is a number in brackets underneath the term. Outside the squares the X axis lists variations on the term RST, as does the Y axis. Late 19th to early 20th century