A traditional flat-bottom boat sails off the island of Norr?ra in the Stockholm archipelago, where the holiday is celebrated best.
在斯德哥尔摩群岛，有一艘传统的平底船驶出诺劳拉岛，这里是节庆气氛最热烈的地方。
2
If the glass were kept hot enough, it would flow over the molten tin until the top surface was also flat, horizontal and perfectly parallel to the bottom surface.
如果玻璃保持足够的温度，它就会在熔化的锡中流动，直到顶部表面也变得平整、水平，与底部表面完全平行。
3
So engineers added details such as a gently sloping rear hatch, a flatbottom and small creases and fins that manage airflow.