The Rockshelter Castle 'Fracstein'/Seewis GR, the Cave 'Drachenhoehle' and a Rare Geometric Figure

In the Rhine valley north of Chur and between the cantons of Graubuenden (GR) and St.Gallen (SG) (Switzerland) one can find some interesting (prehistoric) geometric relations.
A straight line goes from the former castle 'Castlins'/Jenaz GR (772.240/201.135) over the rockshelter castle 'Fracstein'/Seewis im Praetigau GR to the former castle 'Winegg'/Malans GR (762.095/207.060), and 'Castlins' is equidistant (11.70 km, always measured horizontally) from 'Winegg' and from the former castle 'Ober-Ruchenberg' (P.1058)/Trimmis GR.
This indicates once more that the majority of mediaeval castles must have been built on prehistoric "important places", often not for "strategic reasons". ('Ober-Ruchenberg' on over 1000 metres altitude was certainly not practical ...)
The rockshelter castle 'Fracstein' was equidistant (4.02 km) from the former castle 'Winegg' and from the church Fanas GR, this church again from 'Winegg' and from the church Jenaz GR (7.46 km).
"Rockshelter castles" similar to 'Fracstein' are particularly prominent in the cantons of Valais and Ticino ("case dei pagani" = "pagan dwellings").
A straight line leads from the rockshelter castle 'Fracstein' over the former castle 'Friewis' (P.546)/Untervaz GR to the church of Vaettis/Pfaeffers SG. 'Fracstein' is equidistant (6.43 km) from the former castle 'Friewis' and from the church in Furna GR; the straight line  church Furna  -  'Friewis'  goes exactly to the chapel Vasoen/Pfaeffers.
The former castle 'Lichtenstein'/Haldenstein GR is then equidistant (7.06 km) from the former castle 'Friewis' and from church Vaettis; the same distance a third time between church Vaettis and the church Valens/Pfaeffers.
The straight line  church Valens  -  church Vaettis  goes over the cross 'Findels' (P.1653)/Pfaeffers (754.020/200.815) and reaches beyond the earthwork Vaettis (P.972) (752.450/197.190).
The cross 'Findels' is equidistant (3.94 km) from this earthwork and from the cave 'Drachenloch' (dragon hole)/Vaettis (750.435/199.070), frequented already in very ancient times (Moustérien).
Quite a few years ago the question was raised if especially (artificially) deposited bones and skulls of (now extinct) cave bears found in this cave could indicate a "bear cult". The results of this study would point to 'Drachenloch' as a "cult cave".
The straight line  cave 'Drachenloch'  -  cross 'Findels'  can be prolonged to the church Mastrils GR.
The cave 'Drachenloch' is also equidistant (9.87 km) from the former castle 'Friewis' and from the former (now carried off by a cement company) neolithic 'Haselbodenkopf' (P.722.6)/Untervaz.
'Friewis' is equidistant (4.52 km) from 'Haselbodenkopf' and from the church Malans GR; the straight line  'Haselbodenkopf'  -  church Malans leads to the former castle 'Klingenhorn'/Malans.
Returning to the straight line  former castle 'Lichtenstein'  -  earthwork Vaettis  (7.06 km), the same distance can also be established a fifth time between this earthwork and the cross 'Oberboden' (P.1505)/Pfaeffers (753.375/209.255).
The straight line  earthwork Vaettis  -  cross 'Oberboden'  goes over the cross 'Tritt'/Pfaeffers (752.840/200.205); the cave 'Drachenloch' is equidistant from this cross and from the church Vaettis (not indicated in graph).
Surprisingly, a sixth time the same distance of 7.06 km is found between cross 'Oberboden' and the former castle 'Friewis', which together with earthwork Vaettis and former castle 'Lichtenstein' leads to the precise geometric (and rare) figure of a rhomb !
This is hardly casual and underlines the interest of our distant ancestors in geometric relations between cult monuments and places.
Similar tendencies were found in the previous studies Praehistorische Spuren rund um St.Gallen III and VIII, but never led to an equilateral rhomb.
Proof of the non-casualty of this rhomb: the diagonal  cross 'Oberboden'  -  former castle 'Lichtenstein'  (11.07 km) is also the distance between cross 'Oberboden' and the former castle 'Aspermont'/Trimmis, and, regarding the other diagonal, the former castle 'Friewis' is equidistant (8.78 km) from the earthwork Vaettis and from the former castle 'Solaver'/Gruesch GR (both cases not indicated in graph).
Also not indicated in graph: the straight line  former castle 'Lichtenstein'  -  church Mastrils  goes precisely over the (protestant) church Untervaz; the church Mastrils is equidistant (4.23 km) from this church and from the thermal spring of Pfaeffers in the Tamina gorge (755.865/204.030).
Back to the straight line  church Fanas  -  rockshelter castle 'Fracstein'  which leads exactly to the chapel Vasoen, like the above mentioned straight line  church Furna  -  'Friewis' !
Not indicated in graph: the former castle 'Ober-Ruchenberg' is equidistant (10.66 km) from this chapel and from the chapel 'St.Margrethen'/Pfaeffers.
Finally, the rockshelter castle 'Fracstein' is equidistant (9.43 km) from 'Haselbodenkopf', from the church Jenaz and from the church in Flaesch GR.