Carcer carries single points in the Fire and Earth rows and double points in Air and Water, six points in all.
Reading the four rows
Read from the top down, the rows are Fire, Air, Water and Earth. In the common reading a single point marks the element active and a double marks it passive, so Carcer reads as an active Fire and an active Earth with a passive middle. Drawn out, the figure shows a single point at the top and a single point at the bottom with the two doubled rows between them, which is the visual reason for the name: something shut in on both ends.
What flipping it produces
Turn every row from single to double and back and Carcer becomes Coniunctio, whose points sit in exactly the opposite arrangement. The pairing is a fact about the point structure and not a claim about how the two are read.
The attributions
This atlas records Carcer under Saturn, the sign Capricorn and the element Earth. The point pattern is intrinsic and can be verified by anyone who draws the figure. The planet, sign and element were attached to the figures by the astrological tradition rather than derived from them, and the Latin handbooks differ from one another on several of the sixteen.
The name means prison. In the Latin tradition the figure is read as restriction, delay, binding and a matter held in place, and it is one of the figures whose traditional meaning and whose drawn shape agree with one another closely enough that the reading is easy to remember.