A shape's stroke paint is only half the story. The Stroke Style is also an important component of how an outline is drawn. Primarily the style controls the thickness of the line drawn, but it also can be used to create a dashed line. The setting for thickness is specified in pixels, and creating a dashed line is as easy as picking the style from the list. The effect of the thickness and dash pattern settings is fairly self-explanatory, but the other stroke settings are a bit more subtle. You can notice their effect more readily on thick lines.
You can access the Stroke Style in the Property Editor under Appearance.
Cap style is a setting that controls what happens at the end of a line segment. You can either have the line simply be terminated with no decoration (#1), round-off the end with a semi-circle (#2), or cap the end with a square (#3).
Join style is a setting that affects how a line is drawn where two segments meet (a corner). The default setting is called a miter join (#1), where the stroke is extended into a point to make 90-degree angle. The other options are rounded corners (#2) or beveled edge corners (#3).
Miter Limit style joins can become a problem for very sharp angles. With a sufficiently sharp angle, the miter decoration can become extremely long. To control this, there is a miter length setting to limit the length of a miter decoration. The illustration below shows the same miter join with two different miter length settings. The first drawing illustrates the length of the miter join.