Describe completely the locus of centre of a ball, rolling along a straight line on a level floor.

Draw and describe the locus of a point in rhombus ABCD which is equidistant from AB and AD.

Describe completely the locus of point in a plane equidistant from a given line.

Draw and describe the locus of a point in the rhombus ABCD which is equidistant from the points A and C.