The deck plans should have a legend on them. The square generally means 2 convertible twins with an upper and sofa. The single dot means one overhead bunk and two dots means two overhead bunks, as well as two convertible twins.
Carnival Pride-Western Caribbean Feb 2015
Scenic Emerald-Paris to Barcelona Sept 2013
Freedom OTS-E. Caribbean March 2013
Scenic Emerald Amsterdam to Budapest Sept 2012
Emerald Princess-S. Caribbean Jan 2012
AMA Amalegro Prague to Paris Sept 2011
Oceania Insignia Venice -Barcelona -September 2010
Coral Princess Panama Canal FLL to LA Dec 2009
Emerald Princess Baltic Aug 2009
Caribbean Princess S. Caribbean B2B Nov 2008
This is from the Triumph but I imagine all the ship have the same notations.
ACCOMMODATIONS SYMBOL LEGEND
Triangle - Twin Bed and Single Sofa Bed
Star - 2 Twin Beds (convert to King) and Single Sofa Bed
1 dot - Twin Beds (convert to King) and 1 Upper Pullman
2 dots - Twin Beds (convert to King) and 2 Upper Pullmans
Square - 2 Twin Beds (convert to King), Single Sofa Bed and 1 Upper Pullman
Cross - 2 Twin Beds (convert to King) and Double Sofa Bed
Diamond - Stateroom with 2 Porthole Windows
Less than sign - Connecting staterooms (ideal for families and groups of friends)
Sun - Twin beds do not convert to a King Bed.