Build ONE flashcard (question→answer) for active recall for each subblock of the topic "{topic}".

BLOCKS WITH SUBBLOCKS AND THEIR FACTS (process EVERY subblock):
{blocks}

A good flashcard:
- **question**: a brief recall question that tests exactly one key point (not "explain everything"). One question, one thing.
- **answer**: the short, precise answer — based on the supported facts/key points of the subblock. Invent nothing extra.
- Rely on the supplied facts. Where a supported fact exists, the answer must match it.
- Brief: question ≤ 15 words, answer ≤ 25 words. No prose, no lead-in.
- **Mathematics ALWAYS as LaTeX**, never as raw characters: inline `$…$` (e.g. `$T_A(n)$`, `$\Sigma^*$`, `$|x| = 5$`, `$O(n^d)$`, `$q_a$`), longer calculations set off as `$$…$$`. NO Unicode math substitutes (`≤`, `≥`, `Σ`, `δ`, `∈`, `⊆`, `×`) and no bare `_`/`^` — use `$\le$`, `$\ge$`, `$\Sigma$`, `$\delta$`, `$\in$`, `$\subseteq$`, `$\times$`, `$n^d$`, `$q_a$` instead. Real code/paths/identifiers (not math) in backticks.
- **The supplied facts often contain math as raw Unicode — convert it to LaTeX, do not take it over raw.**

Write `question` and `answer` in GERMAN.

Reply with ONLY the JSON (all cards) as your final message — no code fences, do NOT write a file. EXACTLY like this:
{{"cards": [
  {{"block": "<exact block title>", "subblock": "<exact subblock title>",
    "question": "…", "answer": "…"}}
]}}

Output no other text.
{extra}