
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Let $x$, $y$, $z$ be lines or planes in space. For the following four situations: ① $x$, $y$, $z$ are all lines; ② $x$, $y$ are lines, $z$ is a plane; ③ $x$, $y$ are planes, $z$ is a line; ④ $x$, $y$, $z$ are all planes. Among these, the situations where the statement "$x \parallel z$ and $y \parallel z \nRightarrow x \parallel y$" is true are __________.

Present the answer in LaTex format: \boxed{Your answer}
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