Untitled (Full Colored Butterfly 761) announces itself through sheer chromatic force, its radiating wedges of colored pencil fanning outward from a central axis in a composition that is simultaneously precise and sensuous. Grotjahn constructs the butterfly format through rigorous perspectival logic, layering hues with a density and control that transforms the humble medium of colored pencil on paper into something closer to optical architecture. At 120.9 by 96.5 centimeters, the work commands a physical presence unusual for works on paper, and the handmade texture of each drawn line remains legible beneath the saturated surface, reminding the viewer that this is an accumulation of patient, deliberate mark-making rather than mechanical reproduction. The butterfly series sits at the center of Grotjahn's sustained investigation into the relationship between geometric structure and perceptual experience, drawing on a lineage that includes the formal rigor of Kandinsky, Malevich, and Mondrian while refusing their austerity. Where those predecessors often subordinated color to system, Grotjahn allows the two to operate in productive tension, so that the symmetrical armature of the composition reads simultaneously as a window with recession into depth and as a flat, almost decorative surface pattern. This oscillation, never fully resolving in either direction, is precisely where the work generates its energy and its enduring visual interest. Signed and offered from an important American private collection, this is a strong example of Grotjahn's work on paper at a scale and ambition that rivals his painted output. Works of this quality from established private holdings carry both the provenance and the material integrity that serious collectors seek, and the full color saturation of this particular example places it among the most visually arresting works in the series.