Better in pairs...

[bryantpau]

http://five.flash-gear.com/npuz/puz.php?c=v&id=4299056&k=20996959

http://five.flash-gear.com/npuz/puz.php?c=v&id=4299058&k=62925250

http://five.flash-gear.com/npuz/puz.php?c=v&id=4299059&k=63062446

http://five.flash-gear.com/npuz/puz.php?c=v&id=4299060&k=60155423