change only the edge · the interior must answer
Five fixed edge values determine the first harmonic field. Activate any boundary point to change a condition; the interior cannot be edited directly.
felt
Changing one fixed value at the edge reorganized curves throughout the interior. The field visibly relaxed toward a new solution even though you never touched a contour.
found
The drawing is a harmonic solution to boundary conditions. Interior values repeatedly average their neighbors toward ∇²φ = 0, and the visible curves are equipotential contours extracted from that scalar field.
carry
Many outcomes are authored indirectly. Interfaces, structures, policies, physical systems, and optimization problems can be changed more powerfully by changing their boundary conditions than by editing each result individually.