problems visualising the power transfer in a simple circuit
The power of the energy flow out of the leftmost current source is plus 24 watts. The other current source outputs as much and the total 48 watts flows into the 12V voltage source, but that was not asked in the problem.
Physics has got it clear that the energy is stored into the electric and magnetic field in its way between the source and the target which sinks it. It's not inside the metal of wires, it's in the space around and between the wires. A sound visualization would be a thick arrow between the horizontal wires with text P=24W. The direction of the arrow should be from left to right. You should have more room so that you could draw the arrow bypassing the other current source.
The total 48W into the voltage source could be a drawn as a wide arrow with splitted tail. One half of the tail starts from the leftmost current source and the other half starts from the rightmost current source.