Door ingeniously adopts an intricate part of the contemporary urban life to present how childhood radiates its innocent warmth and goodwill to the world in its unique way, especially in the confining urban living space. While the story is characteristic of contemporary life, the author fully respects the child's self-protecting principle of “never opening the door for strangers,” and turns the frustration in urban life into a special and warm encounter from the perspective of childhood.

The illustration is concise, clean, simple, and aware of the presentation of the child's perspective. In addition to ordinary paints, the application of collage brilliantly blends household materials such as fabrics and yarn in the picture book. Soft-colored fabrics and threads of cotton and linen are used to present walls, clothes, bay windows, cat's eyes, tables, chairs, cactuses, and the like. The naturally cordial atmosphere in daily life that the former brings forth tones down the apathy from modern architectural icons in these images, such as apartment buildings, doors, windows, and fences. The materials of illustration and of content agree visually, which brilliantly echoes the presentation of story and shows the wisdom of the picture book illustration design.

This work attempts to find an actual “gap” for us to communicate and warm each other from the iconic “door” that symbolizes urban detachment. The reality-related hope and despair projected from the “gap” all worth our pensive contemplation.