Given that two blocks at different temperatures are kept in contact.
The initial temperature T₁ is greater than the initial temperature T₂.
From the second law of thermodynamics, heat flows from the body at a higher temperature to the body at a lower temperature when they come in contact.
Thus the heat flows from the block on the left to the block on the right until they achieve thermal equilibrium.
Thus after several hours, the temperatures of the block will be equal.