Idea generation in design productive process often occurs within brainstorming sessions. Linking ideas is the key mechanism in this process to produce design. Through linking ideas, a graph-like knowledge is representing the individual memories with the nodes and arcs that are the ideas and the links between ideas respectively. Design is the process of puzzle-making, such thinking process is similar to play jigsaw. This research applies a computational tool (called DIM) to produce a graph-like knowledge including diverse jigsaw-like ideas and their relationships. Then we use protocol analysis to understand how designers organise the ideas. The objective is to find the hidden patterns of assembling ideas in the design productive process. Some feasibilities of the game mechanisms are proposed in this paper.