Paragliders

We sat and watched the paragliders circling above us, and I told her what my brother had told me, about how the geological fault that built the cliffs they sailed from was still moving the landscape today, and the paragliders were the only way to monitor the shifting ground. Halfway through I realised it was a lie, one of those soap bubble lies that survives until you touch it. But she believed it, just as I had, and I let her. So does that make me a liar?