If each "dot" of ketchup is an object, you'll need to record (probably to an array) each object's data (position, size, angle, etc.), and then use that data to recreate the pattern of objects as needed. It gets trickier if the pattern needs to be redrawn at different scales or angles. If so, you'll need to calculate each objects relative position/size/angle when redrawing.
If the objects are only being used for visual purposes, you would probably have a much easier time using the paster plugin to create and copy the ketchup pattern.