# Don't look back, crazy clown

INSANE                RETROSPECT


and see if you can get them to exchange places by transferring one letter at a time. With each transfer, you may also rearrange (anagram) each word in any way you choose. However, each side must always remain a valid English word.

You are finished when you have reached

RETROSPECT            INSANE


All the intermediate words should be fairly common, so you shouldn't have to reach for your dictionary. There is one word along the way which might seem a little unfamiliar to some, so I will give it to everyone as a guidepost: INTERCASTE.

Here is an unrelated example just to illustrate the movement:

MAGISTRATE          DENSER
|     .           |
|       .         |
|         I       |
|           .     |
v             .   v
STRATAGEM           DENIERS
|     .           |
|       .         |
|         T       |
|           .     |
v             .   v
MEGASTAR            RESIDENT
|             .   |
|           .     |
|         N       |
|       .         |
v     .           v
MAGNETARS           DIETERS
|     .           |
|       .         |
|         A       |
|           .     |
v             .   v
|     .           |
|       .         |
|         M       |
|           .     |
v             .   v
STRANGE             DIAMETERS
|             .   |
|           .     |
|         D       |
|       .         |
v     .           v
GRANDEST            STEAMIER
|             .   |
|           .     |
|         I       |
|       .         |
v     .           v
|             .   |
|           .     |
|         E       |
|       .         |
v     .           v
DENIGRATES          MASTER


Notice that at each step, you may transfer in either direction. You are not obligated to alternate between right to left and left to right.

Afterword:

Here is another solution using more familiar words:

INSANE RETROSPECT
CANINES PROTESTER
CRANNIES TREETOPS
CANNERIES PROTEST
NECTARINES POSTER
ENTRANCES RIPOSTE
REENACTS PROTEINS
EASTERN INSPECTOR
ASTERN RECEPTIONS
SENATOR PRESCIENT
REASON INTERCEPTS
PERSONA INTERSECT
PERSON INTERCASTE
OPENERS INTERACTS
PIONEERS TRANSECT
INTERPOSE TRANCES
PROTEINS REENACTS
RIPOSTE ENTRANCES
POSTER NECTARINES
PROTEST CANNERIES
TREETOPS CRANNIES
PROTESTER CANINES
RETROSPECT INSANE

• Pennywise.....? – North Sep 9 at 19:52

Amazing puzzle! Found a solution after a couple of hours of hunting (I hope that all the words I used are allowed in this puzzle)

     INSANE             RETROSPECT
|             .   |
|           .     |
|         T       |
|       .         |
v     .           v
INANEST            RECEPTORS
|             .   |
|           .     |
|         C       |
|       .         |
v     .           v
INSTANCE           REPOSTER
|             .   |
|           .     |
|         E       |
|       .         |
v     .           v
TENANCIES           REPORTS
|             .   |
|           .     |
|         T       |
|       .         |
v     .           v
ANCIENTEST          PROSER
|             .   |
|           .     |
|         R       |
|       .         |
v     .           v
INTERSECANT         PROSE
|     .           |
|       .         |
|         N       |
|           .     |
v             .   v
INTERCASTE          PERSON
|     .           |
|       .         |
|         A       |
|           .     |
v             .   v
INTERSECT           PERSONA
|     .           |
|       .         |
|         T       |
|           .     |
v             .   v
ENTICERS            OPERANTS
|             .   |
|           .     |
|         O       |
|       .         |
v     .           v
RESECTION           PARENTS
|     .           |
|       .         |
|         I       |
|           .     |
v             .   v
TENSCORE            PAINTERS
|             .   |
|           .     |
|         P       |
|       .         |
v     .           v
COPRESENT           RETAINS
|             .   |
|           .     |
|         R       |
|       .         |
v     .           v
PRECENTORS          TINEAS
|     .           |
|       .         |
|         N       |
|           .     |
v             .   v
RECEPTORS           INANEST
|             .   |
|           .     |
|         T       |
|       .         |
v     .           v
RETROSPECT          INSANE  

• Wow, wow! You definitely solved it! Great work. All of your steps are correct, and I have confirmed that all of these are in fact English words. And, I really built my vocabulary today! Not only did I have to reach for my dictionary, but some of these are not even in my dictionary! In case you're interested, there exists another path using more common words. If no one can find it by tomorrow, I will present it. – SlowMagic Sep 10 at 13:22
• BTW, in the step immediately prior to INTERCASTE, you show an "S" being transferred, but I think you meant it to be an "N". – SlowMagic Sep 10 at 13:22
• Thank you very much for confirming! :D – Zoir Sep 10 at 13:24