Automatic data plotter

Claim 1

DATA PLOTTING MEANS COMPRISING A PLOTTING SURFACE HAVING A PLURALITY OF SUBSTANTIALLY EQUAL SIZED SQUARES FORMING A CHECKERBOARD PATTERN; SELECTED ONES OF SAID SQUARES BEING FORMED OF TRANSLUCENT MATERIAL OF AT LEAST TWO DIFFERENT COLORS; A LIGHT SOURCE POSITIONED BENEATH SAID SURFACE; DETECTION MEANS MOVABLE OVER SAID SURFACE FOR GENERATING FIRST SIGNALS REPRESENTATIVE OF THE SQUARES PASSING BENEATH SAID DETECTION MEANS; SAID DETECTION MEANS COMPRISING FIRST AND SECOND OPTICAL SENSING ASSEMBLIES POSITIONED AT SPACED INTERVALS A DISTANCE LESS THAN THE WIDTH OF EACH SQUARE; EACH OF SAID ASSEMBLIES COMPRISING BEAM SPLITTING MEANS FOR SPLITTING A BEAM INTO TWO DIRECTIONS; TWO LIGHT DETECTION MEANS EACH PLACED IN ONE OF THE TWO SPLIT LIGHT PATHS; EACH OF SAID LIGHT DETECTION MEANS BEING SENSITIVE TO A DIFFERENT COLOR.