|  On a line, you cannot have A between B and C, and B between A and C



on the line, some-point2 is located between some-point1 and that-point1
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error one : some-point2 is located between a point and the same point


on the line, some-point is located at some-distance1 from the start
on the line, that-point is located at that-distance2 from the start
that-distance1 is not equal that-distance2
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error two : that-point is located in more than one place on the line


on the line, some-point1 is located at some-distance1 from the start
on the line, some-point2 is located at some-distance2 from the start
that-distance1 is less than that-distance2
on the line, some-point3 is located at some-distance3 from the start
that-distance2 is less than that-distance3
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on the line, that-point2 is located between that-point1 and that-point3


on the line, this-point is located at this-distance from the start
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            B                        1
            C                        4
            A                        2
            B                        3