In Interstate, most stroke widths are all equal, and the lowercase letters all have a very tall x-height.
A- Flattened apex and equal stroke width
a- Double story, oblique head, and large x-height
d- large counter and an angled or oblique terminal or ascender
G- Equal stroke width and no spur
g- Single story, large and open bowl, and oblique finial
M- Low sitting central junction, pointed central junction, and flat apexs'
Q- Straight angled tail, consistent stroke width
x- tall x-height and consistent stroke width
R- Junctions (stem and leg) are far apart and the leg is oblique or angled
t- Tall x-height, angled or oblique ascender, upright and curved finial
4- Flat apex, consistent stroke width, angled and shaped like a right triangle, and low junction
?- Dot is a perfect circle and consistent stroke width