The flag of Iceland consists of a blue cross on a white background, with a red cross inside the blue cross. The aspect ratio of the flag is 18:25, and the geometric properties are as follows:

• The red cross measures 10% of the flag's width and 40% of its length.
• The blue cross measures 1/9 of the flag's width and 4/9 of its length.
• Each arm of the blue cross ends in a small, white rectangle.

The color codes for the flag are:

• Blue: #005BAB (Pantone 286 C)
• White: #FFFFFF (Pantone White)
• Red: #EF2B2D (Pantone 186 C)

These colors are defined by their Pantone color codes, which are commonly used in printing and design.