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

; Search for games with that have either two light-squared white
;bishops, two dark-squared white bishops, two dark-square black
;bishops. or two light-square black bishops.

;There are two ways to do this. One is to simply have a giant :or with 4
;:piececount clauses in the or:

;(position
; :or(
;   (position
;     :piececount   B[a1,a3,a5,a7,b2,b4,b6,b8,c1,c3,c5,c7,d2,d4,d6,d8,e1,e3,e5,e7,f2,f4,f6,f8,g1,g3,g5,g7,h2,h4,h6,h8] 2 9 )
;   (position 
;     :piececount   b[a1,a3,a5,a7,b2,b4,b6,b8,c1,c3,c5,c7,d2,d4,d6,d8,e1,e3,e5,e7,f2,f4,f6,f8,g1,g3,g5,g7,h2,h4,h6,h8] 2 9)
;    (position
;     :piececount b[a2,a4,a6,a8,b1,b3,b5,b7,c2,c4,c6,c8,d1,d3,d5,d7,e2,e4,e6,e8,f1,f3,f5,f7,g2,g4,g6,g8,h1,h3,h5,h7] 2 9)
;   (position
;     :piececount B[a2,a4,a6,a8,b1,b3,b5,b7,c2,c4,c6,c8,d1,d3,d5,d7,e2,e4,e6,e8,f1,f3,f5,f7,g2,g4,g6,g8,h1,h3,h5,h7] 2 9)
;  )
;)

; But a more elegant way is to use the following code, which relies on
; the fact that flipping the board horizontally changes the color of the
; squares:

(match
 :pgn heijden.pgn
 :output samecolorbishops.pgn
 (position
  :piececount
  B[a1,a3,a5,a7,b2,b4,b6,b8,c1,c3,c5,c7,d2,d4,d6,d8,e1,e3,e5,e7,f2,f4,f6,f8,g1,g3,g5,g7,h2,h4,h6,h8]
  2 9
  :flipcolor
  :fliphorizontal
  :markall
  )
)

After executing this with "> cql SameColorBishops.cql" there are 283 studies found in the Harold van der Heijden Database 2015.
NB. When you see {MATCH} in the text, it means that cql has found the position asked for.

Below only 5 studies ares showed: