pawnchain c5-d6-e5, piece sac c5.cql

cql()

flipcolor {
    {result 1-0}
    line --> {
        wtm {movenumber < 21} { power A <= power a + 1 }
        pc5 pd6 pe5 Pd5
    } --> [QRBN]c5 --> pc5 --> [KQRBN]c5
}