Heavy, tight brindle:
With this Shih Tzu, brindle covers the entire body from head to paw and the stripes are tight together.
Ake, at 18 months old, photo courtesy of Johanna
Age-related grayed brindle:
As Shih Tzu dogs age, gray hairs can come in. This senior was once a dark brindle all over and now has noticeable grays throughout the coat, concentrated on the main body.
Oreo, at age 13, (right before he passed over; RIP Oreo),
photo courtesy of Heather S.