(;
AB[ba][ab][da][db][dc][cd][ce][bf][af][df][kb][ka][kc][lc][mc][nc][oc][pb][pa][qc][rc][sc][qd][re][sd][rf][sf][rs][rr][rq][os][or][oq][pq][pp][qo][ro][so][po][br][bs][as][es][er][eq][dq][dp][do][dn][cm][dm][bm][co][bo][ao][al]
AW[ac][bc][cc][cb][ca][bd][be][ae][ra][rb][sb][qb][ob][nb][na][la][lb][mb][pc][pd][od][qe][qf][oe][ne][nf][og][pg][pf][rp][sp][sq][sr][qq][qp][qr][pr][ps][ar][aq][ap][bp][cp][cq][cr][cs][dr][fs][fr][fq][fp][ep][eo][en][em][dl][cl][bl][ak][bk][el][cn][bn][an]
TR[pb][pa][ba][ab][rs][rr][rq][al]
C[Seki appears in many different forms.  This diagram shows just a small sampling:

Lower right:  a very common 3 stone seki with no internal eyes.
Upper left:   seki with 2 diagonal (but unconnected) stones.
Upper right:  2 connected stone seki, but with internal eyes.
Lower left:   the amazing hane seki theme from a Dosetsu masterpiece.

But can you construct a seki with exactly 2 connected internal stones and no internal eyes?  Has such a seki occurred in a pro game?  If so, where?  If not, why not?]
(;
W[am]
C[In the lower left corner, White cannot capture here!];
B[al];W[am];B[ds];W[bq];B[bs]
C[And White loses the semeai.]
)
    (;
    B[am]
    C[And yet Black cannot capture here either!];
    W[bn];B[ds];W[bq];B[bs];W[cn]
    C[And now Black loses the semeai!

Black cannot connect, and White cannot capture, the Black hane stone!  So the game will end with neither player touching the original position.  A truly bizarre seki.]
    )
)

