There are many ways to keep a ladder from slipping. The easiest “put on” her old sneakers or shoes with a rubber sole.
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THE TIMER CONTROLS THE SOUND
The device, whose scheme is published in the journal "Popular electronics" (USA), produces a positive pulse when a sound (for example, firing of the gun) reaches the microphone B1 (see...
APPLES – A BOTTLE OF
Now it offers a lot of options, the use of large plastic bottles from under water and juices. I want to share one more: you can make arrangement to collect apples from high branches. To...