# [Python 2], <s>287</s> <s>271</s> <s>270</s> 276 bytes

<!-- language-all: lang-python -->

    import time,random
    r,n=input()
    c=n*-~r or-r
    while c:
     c-=1;L=[list(' '*i+'\\'+'  '*(r-i)+'/')for i in range(r)];x=c%-~r;time.sleep(.1);y=x+1;exec"L[x][y]=random.choice('\xaf/\_'[L[x][y-1]in'\_'::2][y==2*r-x:]);y+=1;"*2*(r-x)
     for l in['']*99+L+[' '*r+'\xaf'*2]:print''.join(l)

[Try it online!][TIO-ji341pg6]

[Python 2]: https://docs.python.org/2/
[TIO-ji341pg6]: https://tio.run/##Jc5LasMwEIDhvU8hAmX0sBzsRSA2uoFvIIsSVKWeYktGUamy6dVdudnNMPDPtz3THHy377huISaScHV1vPmPsFax9gr99p0oq6zyXP5GEqKM1c@MiyO2r4iVqh1GpRd8JAoEOAqYJhBAykyjRCbgDOweIkGCnpTyp6ORmSEr@1aCw/GweSzObbRp2fBUWbSDy86eRp2Nfhr10jR2DmgdhSnf7ufpHfTrLluDHsre911Zlep4lLk3JSWK7cS7w5FZRQ7EUhAawPDrVYxCH@Io/pPAO9NvEX0CaL4Cerqwfb/U7R8 "Python 2 – Try It Online"

Does not clear the screen on tio, but works in a console.

Gif of it running:

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/Vw7w4.gif