In By the Sea, Piet Mondrian presents a vibrant marine scene characterized by bold colors and geometric shapes. The painting features a dynamic interplay of blues, yellows, and whites, evoking the essence of the sea. The composition is abstract yet suggests movement, reminiscent of waves and the horizon.

This work reflects Mondrian's transition towards abstraction, moving away from representational art. The painting is executed in oil on canvas, showcasing Mondrian's signature style of using primary colors and simple forms. Viewers can observe the structured arrangement of colors, which creates a rhythmic flow across the canvas. The dimensions are approximately 60 x 80 cm, making it a medium-sized work that draws attention without overwhelming the viewer.

The use of color and form invites contemplation and exploration. By the Sea was created during a pivotal time in Mondrian's career, as he began to explore abstraction more deeply. This work is significant because it marks a shift from his earlier representational style to the geometric abstraction he is known for today. Interestingly, Mondrian was influenced by the natural landscapes around him, which he simplified into forms and colors.

This painting exemplifies his journey towards a new visual language that would later define modern art.