The Growing Caterpillar

The Growing Caterpillar is a toolkit for therapist used in play therapy that lets children build their emotions one piece at a time. Each block represents a feeling like happiness, sadness, or anger through color and texture. The caterpillar lights up and reacts to their heartbeat, showing how feelings work not in isolation but can build to make complex emotions

We used biosensors (like ECG) to read heart signals and created a simple, playful way for kids to connect with their feelings. Instead of labeling emotions, we let them build their own story.

Each block on the caterpillar stands for a basic feeling—like happiness, sadness, anger, or fear. The blocks have different colors and textures that match the emotion. For example, sadness might feel soft and droopy, while anger might feel rough or sharp. Children can pick the blocks that feel right to them and build their caterpillar however they like.

This tool is made for non-directive play therapy, where the therapist doesn’t guide or ask direct questions. Instead, the child leads the way. The caterpillar gives them a safe and fun way to show how they’re feeling.

It’s not about figuring out the exact emotion. It’s about helping children notice their feelings, explore them, and slowly build emotional awareness through play.

For therapists, the caterpillar becomes a gentle and creative way to connect with children. It gives space for emotional expression to happen naturally—on the child’s own time, in their own way. Whether used in one-on-one therapy or group settings, it can open up conversations and help children feel seen and understood.