I'm a little confused or uncertain rather about the best way to finder the beginning of castles made of sand
----3-|/5----5/8----8/10---10\8--- 8-|\5----5\3----3/5---------|---p3---
----1-|/3----3/6----6/8-----8\6----6-|\3----3\1----1/3---------|---(3)---
------|-------------------------------|-------------------------|-------------3-|/5----5/8----8/10---10\8---8-|\5----5\3----3/5---------|---(5)----
------|------------------------------|-------------------------|--------------1-|/3----3/6----6/8-----8\6----6-|\3----3\1----1/3---------|---(3)---