Jelly, 8(削除) 8 (削除ここまで) 7 bytes
A monadic link returning a list of strings.
ḲOr97ỌKYḲOr97ỌK
ḲOr97ỌKYḲOr97ỌK - a monadic link taking a string, e.g. "ab c"
Ḳ - split at spaces --> ["ab", "c"]
O - get ASCII codes --> [[97, 98], [99]]
r97 - build descending range to 97 --> [[[97], [98, 97]], [[99, 98, 97]]]
Ọ - turn back into ASCII --> [["a", "ba"], ["cba"]]
K - join with spaces --> ["a", "ba", " ", "cba"]
Y - join with linefeeds
Jelly, 8 bytes
ḲOr97ỌKY
ḲOr97ỌKY - a monadic link taking a string, e.g. "ab c"
Ḳ - split at spaces --> ["ab", "c"]
O - get ASCII codes --> [[97, 98], [99]]
r97 - build descending range to 97 --> [[[97], [98, 97]], [[99, 98, 97]]]
Ọ - turn back into ASCII --> [["a", "ba"], ["cba"]]
K - join with spaces --> ["a", "ba", " ", "cba"]
Y - join with linefeeds
Jelly, (削除) 8 (削除ここまで) 7 bytes
A monadic link returning a list of strings.
ḲOr97ỌK
ḲOr97ỌK - a monadic link taking a string, e.g. "ab c"
Ḳ - split at spaces --> ["ab", "c"]
O - get ASCII codes --> [[97, 98], [99]]
r97 - build descending range to 97 --> [[[97], [98, 97]], [[99, 98, 97]]]
Ọ - turn back into ASCII --> [["a", "ba"], ["cba"]]
K - join with spaces --> ["a", "ba", " ", "cba"]
Jelly, 8 bytes
ḲOr97ỌKY
ḲOr97ỌKY - a monadic link taking a string, e.g. "ab c"
Ḳ - split at spaces --> ["ab", "c"]
O - get ASCII codes --> [[97, 98], [99]]
r97 - build descending range to 97 --> [[[97], [98, 97]], [[99, 98, 97]]]
Ọ - turn back into ASCII --> [["a", "ba"], ["cba"]]
K - join with spaces --> ["a", "ba", " ", "cba"]
Y - join with linefeeds