Disclosed are techniques for implementing parallel fills for bottom-up electronic design implementation flow and track pattern definition for multiple-patterning lithographic processing. These techniques identify a canvas in a layout and design rules for track patterns and multiple-patterning, where the canvas is not yet associated with any base track patterns. A first shape having the first width is inserted along a first track in the canvas based on the design rules. A custom, legal track pattern is generated by arranging multiple tracks in an order and further by associating the first width with the first track in the custom, legal track pattern. The layout may then be further modified by guiding the insertion of one or more additional shapes with the custom, legal track pattern.