Seq 01 — Fill, mix, drain

Briefing

A small batch machine runs three steps in a row: fill for 2 seconds, mix for 3, drain for 2. START begins the fill. Each step ends by starting the next and switching itself off, so only one output is on at a time. After the drain, everything is off. STOP ends the cycle at any moment. START pressed mid-cycle does nothing. Step 1 is built for you.

Objectives

• START turns on FILL_VALVE only
• After 2 s the fill ends and the MIXER runs alone
• After 3 more seconds the mixer ends and DRAIN_VALVE runs alone
• After 2 more seconds everything is off
• STOP ends the cycle at any moment; START mid-cycle is ignored

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1START → fill only

   The first step runs alone

2. #2After 2.3 s → mix only

   The fill step ends and the mix step starts

3. #3After 5.4 s → drain only

   The mix step ends and the drain step starts

4. #4After 7.6 s → everything off

   The drain step ends the cycle

5. #5STOP during the mix → everything off, and stays off

   STOP ends the cycle at any step

6. #6START during the mix → nothing changes

   START only begins a cycle when every step is off

7. #7START after a finished cycle → fill only

   A second cycle starts cleanly