Cov dev tsis tuaj yeem nce ntaiv, thiab feem ntau ntawm lawv tau kawm los ntawm lawv cov tswv kom yooj yim nce thiab nqis ntaiv. Qee lub sij hawm, thaum tus dev kawm nce thiab nqis ntaiv, nws zoo siab heev thiab nquag khiav nce thiab nqis. Feem ntau hais lus, dev nce ntaiv sai heev. Lawv tsuas rub nce thiab nqis dua.
Raws li qhov xwm txheej hauv tsev tam sim no, qhov tob ntawm chav tsev stairs feem ntau yog nruab nrab ntawm 25 thiab 28 centimeters, thiab qhov siab feem ntau yog siab tshaj 20 centimeters. Kev hais lus, xws li qhov siab thiab dav hlau qhov tob tsim tsuas yog tsim nyog rau tib neeg siv. Rau cov dev, lub dav hlau qhov tob yuav tsum tsis pub dhau 60 centimeters, thiab qhov siab sib txawv yuav tsum tsis pub dhau 12 mus rau 15 centimeters. Xws li staircase tsim yog tsim nyog rau cov dev mus nce thiab nqis.
