Available colors in turtle

There are several ways to specify colors in turtle. The documentation for the pencolor function shows the different approaches:

• You can use string names like "red". This link shows the available colors by name. The names are not case sensitive in Python, i.e., there is no need to capitalize the names as shown in the link.
• You can use hex strings with the RGB color, e.g. "#ff0000" for red. This online color picker can can help you determine the hex string for a color.
• You can specify the color as three numerical arguments with the RGB values. By default those numbers need to be floats in the range 0-1.