no of these puzzles are impossible…

solution for the puzzle within 4 Steps:

http://helios.wh2.tu-dresden.de/~jooschi/boxlist.txt

the colors are abbr. by numbers:

0:=red

1:=green

2:=blue

3:=yellow

start at the top:

0[0, 0] => try [0,0,1,2] means to test: red,red,green,blue

then look at your result: e.g. C=2, P=0, so you go down to:

1[2, 0] => try [0, 3, 0, 3]

^the leeding 1 shows that we had one try yet

test: red,yellow,red,yellow

result: C=1, P=1, so you go down to:

2[1, 1] => try [0, 0, 0, 1]

test: red,red,red,blue

result: C=0, P=1, so you go down to:

3[0, 1] => (3, 3, 1, 2)

round brackets announce solutions (if there are 2 solutions are listed: try one and in case of failure the other)

hope that helps you a bit ;)

ps: is there a need of redesign the solution more clearly?