[qazxcvbnm]

vimrc for 4)

    vnoremap <C-@>s <C-w>sgv
    vnoremap <C-@>v <C-w>vgv

    nnoremap <expr> <C-@>w '@_' .. ((v:count1 + (winnr() - 1)) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>W '@_' .. (((- v:count1 + (winnr() - 1)) % (winnr('$')) + winnr('$')) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>t '@_' .. ((v:count1 - 1) % (winnr('$')) + 1) .. '<C-w>w'
    nnoremap <expr> <C-@>b '@_' .. (((- v:count1) % (winnr('$')) + winnr('$')) % (winnr('$')) + 1) .. '<C-w>w'
    inoremap <C-@><C-@> <C-@>
    map! <C-@>w <Esc><C-@>w
    map! <C-@>W <Esc><C-@>W
    map! <C-@>t <Esc><C-@>t
    map! <C-@>b <Esc><C-@>b
    tmap <C-@>w <C-@>N<C-@>w
    tmap <C-@>W <C-@>N<C-@>W
    tmap <C-@>t <C-@>N<C-@>t
    tmap <C-@>b <C-@>N<C-@>b