Oxalis triangularis... These have the most amazing deep maroon/purple leaves with pretty pale mauve flowers. Such a cute plant and very easy to keep you can even eat the leaves!
Care: These prefer a sunny spot bright so placing them near/away from an East or South-facing window would be ideal. Watch out for direct sunlight or too much light will burn or fade the leaves. Water lightly weekly they won't' do well in being overwatered, I generally water mine Oxalis once they start to drop a little.
Pot size is 12cm and the total height is approximately 22cm tall.