Simplify the following text for a Grade 12 native English-speaking person.
Original: There are four models commonly used for hyperbolic geometry : the Klein model , the PoincarÃ disc model , the PoincarÃ half-plane model , and the Lorentz model , or hyperboloid model .
Simplified: There are three models commonly used for hyperbolic geometry : the Klein model , the PoincarÃ disc model , and the Lorentz model , or hyperboloid model .