Just in case you would like a couple ideas to get started.

Anything goes.

Person


One idea would be a simple "Person" class that would have ivars "firstName" and "lastName" (and others per coder's choice).

The object structure (ivars) would be the two names plus any more.

A "calculation method" you could code a method called "getFullName" that would return the first and last names joined (separated by a space).

A "logic method" could be "hasLongName" that would return true if the full name length is over some
defined length (decided by you). To get the length of a string, use
"aName.length"


Circle, RightTriangle, etc


Shapes could be modeled very closely to the full example (which is a "Rectangle" class).

TemperatureCalculator


If you are feeling more ambitious, you could code up a temperature calculator that would take one temperature in a "base" unit (e.g. say Fahrenheit or other), and then compute other temperatures from that base (one other or as many as you like -- wiki conversions).

A logic method might be "isHot".