The Explore option "markers" is used to create an app to graphically explore eigenvectors and eigenvalues in the plane. For a real 2x2 matrix, a red input vector and a blue output vector obtained by multiplication by the matrix are shown in a 2D plot. Dragging on the tip of the input vector moves the blue output vector. By dragging the input vector around the origin one can find the matrix eigendirections where they line up. When they line up one can adjust the input vector tip on the grid so one can read off what multiple the output vector is, identifying the eigenvalue. This gives a real visual interpretation of what students are doing when they do the algebraic procedure to determine first the eigenvalues and then the eigenvectors of a simple 2x2 matrix.