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+
+- cartesian coordinates
+
+ - always referred to as "col" and "row", not "x" and "y", since
+ the latter often have other meanings.
+
+ - whenever they appear together, __col__ comes first; not row.
+ This is cartesian convention.
+
+ - 0,0 is the "lower left" corner of the device when the
+ manufacturer specifies a canonical orientation.
+
+ - the unit of measurement is the smallest regular resource
+
+ - resources which occupy more than one unit are always addressed
+ by the lower-leftmost unit occupied.
+
+