Radek Szlaga paints his canvases with such a dense layering of colors that the figures he portrays seem to melt into the viscous surface, even as the entire tableau glows with an inner light. But while the sheer materiality of these works indicates that painting is quite literally Szlaga’s primary medium, his recent show in Warsaw, “Freedom Club,” exhibited other components of his practice. For example, Guerilla Potato Plantation, 2012, which entirely occupied one of the show’s four rooms, consisted of slides projected on two walls of the room and, standing in the middle of it, a greenhouse.