Qビスト... フィルターはグラデーションの色を使った不規則な幾何学文様を生成します。

This filter is found in the main menu under Filters → Render → Pattern → Qbist….

The Qbist filter generates random textures. A starting texture is displayed in the middle square, and different variations surround it. If you like one of the alternative textures, click on it. The chosen texture now turns up in the middle, labeled 「Pattern」, and variations on that specific theme are displayed around it. When you have found the texture you want, click on it and then click OK. The texture will now appear on the currently active layer, completely replacing its previous contents.