procedure cross(word1,word2)
local i, j
if i := upto(word2,word1)
then {
j := upto(word1[i],word2)
every write(right(word2[1 to j - 1],i))
write(word1)
every write(right(word2[j + 1 to *word2],i))
write()
}
return
end