from csp import CSP
crossword_puzzle = CSP(
var_domains={
# read across:
‘a1’: set(“bus has”.split()),
‘a3’: set(“lane year”.split()),
‘a4’: set(“ant car”.split()),
# read down:
‘d1’: set(“buys hold”.split()),
‘d2’: set(“search syntax”.split()),
},
constraints={
lambda a1, d1: a1[0] == d1[0],
lambda d1, a3: d1[2] == a3[0],
lambda a1, d2: a1[2] == d2[0],
lambda d2, a3: d2[2] == a3[2],
lambda d2, a4: d2[4] == a4[0],
})