There is a beetle planning a trip. On the first day, he crawls along a straight line for 1 meter. On the second day, he turns 90° (choose to turn left or right) and crawls along a straight line for 2 meters. On the third day, he turns 90°. (Choose to turn left or right) and then crawl straight for 3 meters. Every day, choose to turn left or turn right 90° according to this rule, and then crawl along a straight line for a distance of 1 meter more than the previous day. Can he just stay at the original starting point?
有一只甲虫计划做一趟旅行，第一天他沿着一条直线爬行1米，第二天他转弯90°(选择左转或右转)后沿直线爬行2米，第三天他转弯90°(选择左转或右转)后沿直行爬行3米，每天都依此规律选择向左转或向右转90°后再沿直线爬行比前一天多1米的路程，那么最早在第几天他可以正好停留在原来的出发点上？
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