Which diagram shows the best placement of heat sources to cause the blocks to converge?

To determine the best placement of heat sources for causing blocks to converge, you would typically want to position the heat sources at the edges or corners of the blocks. This arrangement creates a thermal gradient that encourages movement towards the center. Placing heat sources in a symmetrical pattern can also enhance the convergence effect by evenly distributing the heat. Ultimately, the specific diagram would depend on the arrangement of the blocks and the desired convergence behavior.