The SEI has adopted this three-ring symbol to be the unofficial "logo" for the Software Product Line Conferences, as well as for software product line practice in general. The three circles represent the three essential activities of core asset production, product production, and management, respectively.

• The Core Asset Development circle represents the ongoing activity of developing the product line's core asset base. Its outputs are the core assets used in the family of products, and a production plan that tells how to use or tailor the core assets to produce a product.

• The Product Development circle represents the engineering activity of turning out products using the core assets.

• The Management circle represents the activities of technical and organizational management, without which the product line endeavor will collapse.

The circles are intertwined to show that the activities are inexorably linked with each other. No ordering among the activities is implied. Core assets may be extracted from a set of existing products, built before the first product is rolled out, or some combination. There are strong feedback relationships among the three activities. For example, using the core assets in a product may reveal places where the core assets should be enhanced or improved.

These essential activities are defined and discussed further in the SEI's Framework for Software Product Line Practice.