su·per·pose /ˌsupɚ/
  (vt.)放在上面,重疊
  Su·per·pose v. t. [imp. & p. p. Superposed p. pr. & vb. n. Superposing.]
  1. To lay upon, as one kind of rock on another.
  2. Geom. To lay (a figure) upon another in such a manner that all the parts of the one coincide with the parts of the other; as, to superpose one plane figure on another.
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  superpose
       v 1: place (one geometric figure) upon another so that their
            perimeters coincide
       2: place on top of; "can you superimpose the two images?" [syn:
           superimpose, lay over]