Some mornings, I walk into my classroom before my students arrive and I tape a sign to the board. Several years ago, it started on a large Post-it pad, the kind on a wheeled easel — on a morning when I had planning period first, and I knew, before anyone walked through my door, that I was not okay. The sign tells my students what they need to know: where to find their assignments, that loud or unexpected noises are a trigger for me, and that I cannot process more than one per