The basic idea of the import is following
The start point of the imported pattern will be replaced by the point, where the import will take place. This is like if user will import to point B85, the start point A will be replaced by B85. All points will be drawn from this point as in the imported pattern. The imported pattern points will be renumbered. In this case A1 -> BXX, A2-> BYY ...
The pattern could be imported also as new patter piece. In this case only the letter will be replaced accordingly.
If the imported pattern will have same Increment value, the imported value will discarded. All other values should be merged to the pattern.