
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 the sum of the first $n$ terms of an arithmetic sequence $\{a_n\}$ be $S_n$. Then $S_4$, $S_8-S_4$, $S_{12}-S_8$, $S_{16}-S_{12}$ form an arithmetic sequence. Analogously, for a geometric sequence $\{b_n\}$ with the product of its first $n$ terms as $T_n$, then $T_4$, __________, __________, $\frac{T_{16}}{T_{12}}$ form a geometric sequence.

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