pinn.别针（大头针）；徽章；<口>脚v.钉住；别住；固定住abbr.个人识别码（=Personal Identification Number）,<印>邮编（=Postal Index Number）Pincin平钦

1. Especially the third one describes the pinhole image formation experiment and analogies rectilinear propagation with the archery flight.
   这是世界上最早的针孔成像实验，也是对光的直线传播特性的最早认识。