I can play what if, fix you, talk, x&y, speed of sound, the hardest part, twisted logic, clocks, the scientist, amsterdam, god put a smile upon your face, in my place, don't panic, trouble, everything's not lost and politik all on piano (some with the aid of sheet music, but a lot without - I'm also learning some more like swallowed in the sea and so on) and i can do rhythm guitar (so kinda what Chris does on guitar) for yellow, trouble, the scientist, fix you and don't panic (though these are just playing the chords of them from tabs so its not the EXACT fingering but it still sounds the same - I've only been playing guitar for like 4 months so I do what i can lol). I just got a Coldplay book for guitar that has backing tracks and stuff on it so im looking forward to learning that! Cranking up the sound system and playing along with Coldplay is one of my favourite things to do in the world!