Is there a solution for a straight-bar piece not touching the edge of the rectangle? By rectangle solution, I mean either one of the patterns 15x4, 12x5, or 10x6. By straight-bar piece, I mean the piece of 5 stones in a straight row. Literate pentomino crackers denote this piece with the letter "I".
1 Answer
Here's one solution for the $10{\times}6$ rectangle:
Here are all $11$:
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viiiiilzyy
vxffwwzzny
xxxffwwtny
uxufppwtnn
uuuppptttn
vvvllllzzn
viiiiilznn
vxffwwzzny
xxxffwwtny
uxufppwtyy
uuupppttty
yzzllllvvv
yyzliiiiiv
ynzzwwxffv
yntwwxxxff
nntwppxufu
ntttpppuuu
nzzllllvvv
nnzliiiiiv
ynzzwwxffv
yntwwxxxff
yytwppxufu
ytttpppuuu
tnnnllllpp
tttnnfflpp
tiiiiiffxp
vvvzwwfxxx
vzzzywwuxu
vzyyyywuuu
wwtttxffuu
pwwtxxxffu
ppwtyxzfuu
ppyyyyzzzv
liiiiinnzv
llllnnnvvv
pptttxffuu
ppwtxxxffu
pwwtyxzfuu
wwyyyyzzzv
liiiiinnzv
llllnnnvvv
wwfftttxuu
pwwfftxxxu
ppwfytzxuu
ppyyyyzzzv
liiiiinnzv
llllnnnvvv
ppfftttxuu
ppwfftxxxu
pwwfytzxuu
wwyyyyzzzv
liiiiinnzv
llllnnnvvv
uuxfftttpp
uxxxfftwpp
uuxzfytwwp
vzzzyyyyww
vznniiiiil
vvvnnnllll
uuxfftttww
uxxxfftwwp
uuxzfytwpp
vzzzyyyypp
vznniiiiil
vvvnnnllll
There is only one solution for the $12{\times}5$ rectangle:
There are no solutions for the $15{\times}4$ rectangle.