▪ The different kinds of objects often have a certain amount in common with each
other.
▪ Mountain bikes,
▪ road bikes, and tandem bikes
▪ All kind of the above bicycles share the characteristics of bicycles (current
speed, current pedal cadence, current gear).
▪ Tandem bicycles have two seats and two sets of handlebars;
▪ Road bikes have drop handlebars;
▪ Some mountain bikes have an additional chain ring, giving them a lower
gear ratio.