Repetition, similarity, proportion, consistency and anomaly are key principles of design. Repetition brings unity to a design through consistent reuse of elements and can be regular or irregular. It creates rhythm and flow. Similarity deals with elements that look the same or similar in size, color, or shape, which makes them easy to identify. Anomaly is when one element is different, allowing it to stand out. Proportion refers to the relative size and shape of elements. Consistency builds trust in a design, while lack of consistency causes confusion. These principles give strength, cohesion and guide the audience's eye through a design.