An html version of caterpillar.cql. Created by Gady Costeff and Lewis Stiller.

; In the caterpillar theme, tripled pawns creep up the board one pawn at a time

(match :pgn heijden.pgn :output caterpillar.pgn 
 (position Pb2 Pb3 Pb4 :movefrom Pb4 :moveto .b5
 :gappedsequence
  ((position Pb3 Pb4 Pb5))
 :flipcolor
 :shift
 )
)
After executing this with "> cql Caterpillar.cql" there are 136 studies found in the Harold van der Heijden Database V 2015.
NB. When you see {MATCH} in the text, it means that cql has found the position asked for.

Below only 5 studies are presented: