開けても開けても大統領ー!!
4コマ目のてっぺんは、箱と見せかけて説明書でしたが、その奥にはさらに3つくらい箱がありました(笑)

You open it and open it, and there's the big chief!!
A phrase used in Japan as a synonym for "matryoshka"
At the peak of panel 4, there was a box and a glimpse of the manual, but within that were about three more boxes. :-)