Alexander Calder made this watercolour painting, '7 Circles Abstract', in 1966. It's immediately joyful, isn't it? The colour palette is so simple, but the way Calder has used these colours to create such a playful composition really speaks to his understanding of artmaking as a process. There is something so energetic about the physicality of the medium. The paint is thin and transparent, which allows the white of the paper to shine through, creating a sense of luminosity. I love the way he's built up the composition from simple lines and dots, almost like musical notation. Look at the black lines; how they sit above the blue wash and interact with the circles. The entire image vibrates with energy. Calder was a master of movement, and his influence can be seen in the works of Joan Miró, who explored similar themes of abstraction and playful composition. Ultimately, though, like all great art, it embraces ambiguity, inviting us to bring our own experiences and interpretations.