Design, based on Conic Sections and Linear Functions, is created on a TI-89, TI-89 Titanium, or Voyage 200 Graphing Calculators.
Students will learn how to modify a non-function equation to an equation of a function which can be used on a graphing calculator. They will visually see when the equations are written separately for the upper half and lower half of the circle.  
Students can create a design bases on their own set of equations. They can create any design of which equations can be written.