  Steane's seven-qubit quantum code is a natural choice for fault-tolerance
experiments because it is small and just two extra qubits are enough to correct
errors. However, the two-qubit error-correction technique, known as "flagged"
syndrome extraction, works slowly, measuring only one syndrome at a time. This
is a disadvantage in experiments with high qubit rest error rates. We extend
the technique to extract multiple syndromes at once, without needing more
qubits. Qubits for different syndromes can flag errors in each other. This
gives equally fast and more qubit-efficient alternatives to Steane's
error-correction method, and also conforms to planar geometry constraints.
  We further show that Steane's code and some others can be error-corrected
with no extra qubits, provided there are at least two code blocks. The rough
idea is that two seven-qubit codewords can be temporarily joined into a
twelve-qubit code, freeing two qubits for flagged syndrome measurement.
