There are other translations of this pun in Act II, scene 4 of Romeo and Juliet. A pump is a light shoe. This definition is given in the Modern Text of Romeo and Juliet noted as such in an edition by John A Price. In this line,Romeo makes a pun on another use for "pink" which Mercutio uses in "I am the very pink of courtesy," with "pink" meaning Mercutio is a paragon of courtesy. Romeo plays on the word, saying "pink for pattern." In Romeo's line, "Pink"means to decorate in a perforated pattern."
Then, Mercutio says to keep jesting until the sole is worn out, punning on the words sole/soul; Romeo finishes the pun by saying,
O single-soled jest, solely singular for the singularness! (II,iv,64) [the pun is singular/unusual because of its silly simplicity]