The letters then disappeared in  a backward progression from the 37th to the 57th keyframe.  This gave the illusion that  as each domino turned the letters would appear on the other side and then return to the original state.  When the line of coloured dominoes reappeared, one row was converted to a static ‘graphic’ symbol. At this point 11 layers were created to show the board being created out of one row. Each row moved out of the previous row over a sequence of 5 frames.