The most basic class for a solvable value is Variable. It acts a lot like a float, which makes it easy to work with.
Next to that there's Position, which is a coordinate (x, y) defined by two variables.
To support connections between variables, a MatrixProjection class is available. It translates a position to a common coordinate space, baed on Item.matrix_i2c. Normally, it's only Ports that deal with item-to-common translation of positions.
gaphas.solver.Variable
Variables can have different strengths. The higher the number, the stronger the variable. Variables can be VERY_WEAK (0), up to REQUIRED (100). Other constants are WEAK (10) NORMAL (20) STRONG (30), and VERY_STRONG (40).
gaphas.solver.variable
gaphas.position.Position
gaphas.position.MatrixProjection