http://graphicdesignfundamentals.com/contrast-principles-design/ Contrast: Refers to the arrangement of opposite (light vs. dark colors, rough vs. smooth textures, large vs. small shapes, etc.) in a piece so as to create visual interest, excitement and drama. You can make objects or text stand out by using contrast. This can be done through color, size, alignment, etc. (black/white, large/small, thin/wide, etc).
The red boat stands out more against the white boats.
There is an even space between each cone. https://www.pinterest.com/pin/4433299615807141/ Repetition is simply the process of repeating elements throughout a design Keeping design uniformity with text, picture elements, and design styles allows the viewer to flow easily through your designs.
There are a repeating line of birds. https://www.pinterest.com/pin/267401296603956023/ In terms of art, white space can be referred to as negative space . It is the portion of a page left unmarked.