This circuit creates a superposition, entangles two qubits, attempts to create interference, and measures the qubits.
```python
from qiskit import QuantumCircuit
# Create a circuit with 3 qubits and 2 classical bits
qc = QuantumCircuit(3, 2)
# Prepare a superposition on qubit 0
qc.h(0)
# Entangle qubit 0 with qubit 1
qc.cx(0, 1)
# Apply a Hadamard gate to qubit 1 to create interference
qc.h(1)
# Measure qubit 1 to erase which-path information
qc.measure(1, 0)
# Apply a Controlled-NOT gate with qubit 1 as control and qubit 2 as target
qc.cx(1, 2)
# Apply a Hadamard gate to qubit 0
qc.h(0)
# Measure qubit 0
qc.measure(0, 1)
```'Failed to run program: \'409 Client Error: Conflict for url: https://api.quantum.ibm.com/runtime/jobs. {"errors":[{"message":"You have reached the limit of 3 pending jobs. Please wait for a job to complete or cancel one before submitting anything new.","code":3458,"solution":"Wait until some previous jobs were finished. You can cancel pending jobs to run new jobs.","more_info":"https://docs.quantum-computing.ibm.com/errors"}]}\''