The lower half circle of a half frame diameter touches the center of the bottom frame line, and from the both edges, horizontal lines reach to the left and the right edges of the frame. The shape looks like a hollow or heat is in.
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the hand-shape-sign:
Both sides of fingers stretch out from the palm up naturally extended hand

the hand-movement-sign:
Draw the base shape (記号を宙に描く)

name: ja sound of jar ( ジャ )

f (f of fever/fire)

phonetic value: [ voiced palatal plosive ] (the base is the upside-down shape of #51) (硬口蓋有声破裂音)

definition (single):
heat, a situation having some heat (symbolizing warming up from the bottom)


vi. (the subject) reach warm (熱くなる)
vt. warm or heat (the object) (暖める)

main images in base overlays:

Regarding the image of a heating place:
1) Related to temperature (温度に関連)
2) Related to heat, warm/hot things, once heated things or things to heat

Regarding the symbol as the side-looking:
3) Related to a hollow (くぼんだ形に関係)

examples of base overlay:

Related to temperature (温度に関連)

{{07,08}(degree),52} : (general) temperature (温度)
{07(much),52}: hot, become hot (v. with gd), make ... hot (vt. with #ge) (熱い)
{63(gentle),07,52}: warm, warm oneself (v. with gd), warm up (vt. with ge) (熱い、Dv:暖まる、E:暖める)
{08(little),52}: cold, get cold (vi. with #gd), cold down (vt. with ge) (低温、Dv:冷える、E:冷やす)
{{07,08,52}(temperature),{37(nature),70(space)} sky}: ambient-temperature (気温)
{07(much),{37,70}(sky),52(heat)}: high ambient temperature/hot (暑い)
{63(gentle),07(much),{37,70},52}: warm (あたたかい)
{08(little),{37,70}(sky),52(heat)} : low ambient temperature/ cold (寒い)
{63(gentle),08(little),{37,70}(sky),52(heat)}: cool (涼しい)
{{67,50}(body of a creature),52}: body temperature (体温)
{07(much),{67,50,52}}: (high)-fever, become feverish (vi. with gd) (発熱)
{52,32(unit)}: the basic unit of temperature: degrees centigrade (摂氏温度)
{04(away),52}: cooling, cool down (with ge) (D動詞:冷める、E動詞:冷ます)
{52,25(added)}: warming, be warmed (vi. with #gd), warm-up something (vt. with #ge) (加熱)
{52,23(change)}: change of temperature (温度変化)
{52,40(balance)}: adjustment of temperature (温度調整)
{52,35(continue)}: thermal (保温(用))
{52,35,49(nature/quality)}: retentiveness of heat (保温性)

Related to heat, warm/hot things, once heated things, things to heat (熱さ、熱とかかわるものに関係)

{{37(nature),18(under)} underground, 52}: underground heat (地熱)
{{33,44}(the sun),52}: solar energy (太陽熱)
{12(friction),52}: frictional-heat (摩擦熱)
{06(resist),52}: heat insulating (断熱)
{52,14(go through)}: heat conduction (熱伝導)
{22(origin),52}: heat-source (熱源)
{52,21(go)}: heating , heat (vt. with gd) (熱する)
{52,21,27(repeat)}: reheat (vt. with gd) (再熱)
{{07(much) or 08(little),47}(capacity),52(heat}: heat capacity, calorie (*it's not size of a pan {47,52}) (熱量)
{{08,52},47}}: low calorie
{{07,52},47}}: high calorie
{52,47(container),32(unit)}: calorie as the degree unit
{52,68(heart)} : passion (情熱)
{52(warm),{23,33}(color)}: orange color (橙いろ)
{52,44(spread)}(as a picture like character also): fire, be burnt (vi. with #gd), burn (vt. with #ge) (火・燃える)
{17(up),44,52}: flame (炎)
{{44,52}, 21(go)}: roasting, roast (vt. with gd) (あぶる)
{{44,52},10(place)}: fireplace (暖炉・囲炉裏)
{{02,23}(light),44,52}: spark, sparkle (vi. with gd, vt. with ge) (火花)
{{02,23},44,52}{44,56}(entertainment): firework (花火)
{{44,52}(fire), 29(elemental material)}: oxygen (酸素)
{10(place),37(nature),{44,52}(fire)}: magma (マグマ)
{{15(recognition),30(show)} (message),{44,52}(fire)}: signal fire (のろし)
{09(happening ),{44,52}(fire)}: a fire (火事)
{07(large),09,{44,52}(fire)}: a big fire (大火事)
{06(resist),{44,52}(fire)}: extinguishing a fire (消火)
{66(plant),{44,52}}: bonfire (焚き火)
{{44,52},59(liquid)}: (any kind of ) oil (油)
{67 a part of 'animal,{44,52,59}}: animal fat (動物性脂肪)
{24(solid),{44,52,59}}: grease (常温で固まる油脂)
{{15,59,67}(milk),{(59),52,44}(oil)}: butter (バター)
{46(work),{44,52,59}}: oil/grease for some usage like lubricant/dope/hair dressing (潤滑整髪用などの油性液剤)
{{37,18}(underground),{44,52},59}}: petroleum (石油)
{{44,52},50(thing, goods)}: fuel (燃料)
{{44,52},70(airial),50}: fuel gas (燃料ガス)
{{44,52},{34,35}(stone/ pebble)}: coal (石炭)
{61(after),{44,52}}: ash (灰)
{62(before),{44,52},in 70(air)}: smoke (煙)
{52,59(water)}: hot/warm water (湯)
{52,59,11(limit)}: boiling, boiled water (沸騰)
{52,{59,01}(vapor)}: steam (n.) (蒸気)
{52,{59,01},21(go for)}: steaming, steam (vt. with #gd) (蒸す)
{{35,50}( soil ),52(heated)}: earthenware (焼き物)
{{35,50,52},47(container)}: pottery as vessels/dishes (陶器の器類)
{{35,50,52},24(hard)}: porcelain (磁器)
{48(cover),52}: oven (オーブン・かまど)
{{48,52},21(go)}: baking, bake (かまどで焼く)
{47(container) for 52(heating)}: pan (鍋)
{{47,52},{17,18}( vertically long image )}: cooking pot (深鍋)
{{47,52},28}(flat)}: frying pan (フライパン/料理用鉄板など)
{{10(place),47}(a room),{47,52}}: (the room with pans): kitchen (キチン)

Related to the symbol shape as a hollow /depression (くぼんだ形に関係)

{01(to change to see a symbol),52}: a hollow, sunk, curved in (as a fundamental character) (窪み、凹)
{{01,51}projection,52}: inequality/irregularity (起伏、凹凸)
{01,37(in nature),52}: {hollowed (nature)}: valley (谷)
{10}( place),{01,52}}: basin/an area all surrounded by higher lands (盆地)
{{01,52},70(space)}: hole/an empty space in which something could be, but not go through
{{01,52},60(penetrated)}: hole which something can go through like needle hole and button hole
{{01,52},{17,18}(up and down direction)}: well/vertical hole (縦穴)
{{01,52},{19,20}(horizontal direction)}: cave/horizontal hole (横穴)
{{01,52},46(function)}: utility hole; as manhole (作業用の穴・マンホールなど)
{{{01,52} of {67,69}(torso)}: vagina (膣)
{45(relation) of {(01),(52)} and {(01),(51)}(projection) of {67,69}(torsos)}: sex as activity (性交)
* the notations in ( ) are invisible with other notations.

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