The internal relay

One start button. Three things that must respond to it: the motor, a "running" light on the panel, and a "stopped" light that shows the exact opposite. You could wire the seal-in three times — or you could do what the real print does: seal one internal relay and let everything read it.

The pattern

An internal relay (a CR, for control relay) is a coil with no wire leaving the PLC. It's pure memory — a bit. The relay print seals one in and then fans it out:

   Enable      Start
──────[ ]──┬────[ ]────┬──────( CR1 )     rung 0: seal the MEMORY
           └────[CR1]──┘

──────[CR1]───────────────────( Motor )   rung 1: the machine follows it
──────[CR1]───────────────────( Run light )
──────[/CR1]──────────────────( Stopped light )

Rung 0 is the seal-in you already know — but the coil is CR1, not the motor. Rungs 1–3 are trivially simple: each output just reads the relay.

Why not seal the motor directly?

Because the machine's state and the machine's outputs are different things, and the print separates them:

• One place to change the logic. Tomorrow the customer wants a horn before the motor engages, or a second light. You touch rungs below — rung 0, the actual decision, never changes.
• The inverted output comes free. The stopped light is one XIO contact of the relay. Try building "light ON when the motor is OFF" without a memory bit — you end up duplicating the whole start/stop condition, inverted, and keeping both copies in sync forever.
• It's how the prints you'll maintain are written. Real Logix programs are full of internal bits with names like START_BIT or Internal_Output. Learn to read the pattern and half the program explains itself.

The stopped light is the interesting rung

Rung 3 reads /CR1 — examine-if-open. At rest, CR1 is OFF, the XIO passes power, and the stopped light is ON before anyone touches anything. That surprises people the first time: an output, energized, on a machine that's doing nothing. It's correct — the lamp is reporting rest, not causing it.

Run the real print

Load it in the ladder builder: flip the enable, pulse Start, and watch one bit drive three outputs. Then break it on purpose — delete the CR1 seal branch and see the whole machine die the instant you release the button.