position on the code: N, S, E, W. You must be right.”
They found the North wing, which was clearly marked. Muko was beginning to get the bit between his teeth.
“Now that we know what wing it is, the next thing should be the floor. That Roman II in the code must indicate the floor. We're on the first floor so we have to go up to the second floor!”
Amartia nodded. “All the cards had one of four distinct
values in second position: I, II, III or IV.”
They found the staircase and ran up it.
“The next one's tricky,” owned Muko. “I didn't recognise
the symbol.”
“But I did,” Paidia piped up. “It's the Greek letter 'Sigma'. I know the Greek alphabet so I can convert it to a number. Each alley has a number on the floor at the entrance - have you noticed? We need to find the right alley!”
They rushed down the corridor looking at numbers and finally reached the one they wanted.
“What was the next symbol?” panted Muko.