You are the praetor of Tri, a small triangular-shaped nation bordered on the northwest by the Kingdom of Sauria, on the northeast by the Sultanate of Avia, and on the south by the Republic of Cryosta, as shown below.
Tri is divided into 25 small triangular provinces as shown, each of which has a bustling peasant town at its center. There are also 21 empty monster dens in Tri, which are located at its three outermost corners and at 18 points where the provinces converge (shown as red dots).
In an attempt to boost your flagging economy, you've accepted an enormous sum of gold from your neighbour nations to import 21 of their unwanted monsters, which you plan on placing into your 21 dens (1 monster per den).
The three types of monsters you can import are:
- fire-breating dragons
- man-eating gryphons
- giant trampleodons
You can import as many of each monster as you want, but your neighbour nations have placed some restrictions on where certain monsters can be placed:
- Sauria can only deal with reptilian-type monsters, hence no gryphons may be placed in any of the dens on the border with Sauria
- Avia's terrestrial gardens are laid waste by trampleodons, hence they refuse to allow any trampleodons to be placed in dens on the border with Avia
- Cryosta's buildings are mostly constructed of thatch glued together with paraffin and animal fat, hence no fire-breathing dragons may be placed in dens on their border
Additionally, while the citizens of any one province in Tri can raise arms to defend against one or two types of monster, defending against three types of monsters would overwhelm them. Hence you've resolved that no province may have monsters of all three types in the three monster dens adjacent to it.
Because of these rules, you know that a dragon must go in the northernmost den, a trampleodon must go in the southwesternmost den, and a gryphon must go in the southeasternmost den, but it's up to you to assign monsters to the remaining 18 dens.
Can you meet the demands? Are you up to the challenge?
Respondents are politely encouraged to place answers (i.e. spoilers) in spoiler blocks, so as not to spoil the fun for other puzzlers. :)