overturn, summit, origin
顛 centers on the top or peak of something, and by extension the act of tipping over from that high point. The meanings 'summit' and 'origin' reflect the topmost point, while 'overturn' comes from falling from that peak.
顛 combines 真 (true, real) with 頁 (head). The original idea likely relates to the top of the head or the crown, extending to summit and overturning. The exact phonetic role of 真 is uncertain.
The left side 真 (true) sits beside 頁 (head). Imagine the true top of a mountain as the head of the landscape: the summit. If something at the summit becomes unbalanced, it overturns.
For テン, picture the number ten (テン) balanced precariously at the summit. When it overturns, the ten falls: ten -> テン.