The point down triangle shape, symbolizes indication (「指 示」を意味して、上から指す三角記号)
. . . .
( If you don't understand how to read this page, see here first )

the hand-shape-sign:
the extended three fingers {middle, ring, pinkie}
to symbolize the triangle, facing the palm side to the reader

the hand-movement-sign
quick turn and return of the wrist with the other signed hand

name: u sound of pull (ウ)

ASCII: w (similar mark as the phonetic function)

phonetic value: [ a basic vowel: close back unrounded ]

definition (single):

(function): the indicator of accusative case of a verb... see here for more details.

main images in base overlays:

1) Related to showing something/indication/instruction (指示、表示に関連)
Included symbols for computing terms (コンピュータ用語の簡潔な記号を含む)
2) Special usage for the EL grammatical term related to the function of single #30 symbol
3) Related to the triangle shape of #30, not to its meaning. (記号の三角形に関連)

examples of base overlay:

Related to showing something/indication/instruction(指示、表示に関連)

{01(dot),30}: scale (of a measurement) (めもり)
{{01,30},47(vesel)}: measure-cup
{03(line/needle),30}: an indicator needle to indicate of the tool like a compass and a clock (指針)
{33(to make abstract symbol),30}: indication, point out, show (指示、表示)
{09(intangible matter),30}: topic (題目)
{30,57(wonder)}: which (どちら)
{10(place),30,57}: which place (どちらの場所)
{36(time),30,57}: which time (どちらのとき)
{65(person),30,57}: which person (どちらの人)
{13(same),30}: the same score (同点)
{12(friction),30}: fuzzy (漠然)
{15 recognition,30}: information(情報)
{{15,30}information, {15,61}new}: news
{, 14go through}: message (伝言)
{15,30,21(go)}: dispatch (of a message), send (v. with #d) (送信)
{15,30,47(accepted)}: reception (of a message), receive (v. with gd) (受信)
{10(place),{15,30}}: address (general/as email address) (住所)
{{10,14}{15,30}}: street/road sign (道路標識)
{15,30,33systematical abstract concept}: cord (符合)
{15,30,48(cover)}: envelope (封筒)
{15,30,48,21(heading)}: (a) letter (手紙)
{15,30,{44,52}(fire)}: signal fire (のろし)
: guidance/guide (v. with gd) (案内)
{{14,30}, 10place}: a place to guide as an information center (案内所)
{{15,30}information,46,28}: cards for inform something, such as medical charts/menu
{58being able,15 recognition,30)}: approval (承認)
: translation, translate (v. with gd) ... (These translate, interpret characters are formed by Joseph Bayerl)
{{30,14,23},09}: translation (翻訳)
{{30,14,23},38}: machine translation (機械訳)
{{30,14,23},65}: translator (翻訳家)
{15,30,45,23: interpret (通訳)
{15,30,45,23,65}: interpreter (通訳家)

{11,30(indication)}: designation(指定・指名)
{21(heading),30}:  goal (目標)
{22(origin),30}: principle (主義)
{23(change),30}: signal (信号)
{24(certain),30}: proof/certification (証明)
{30,68(heart)}: a will(意志)
{{30,68},51(power)}: vitality,(気力)
{07(much),30,51,68}: vigorous (気力溢れる )
{08(less),30,51,68}: lose one's vigor (vi.) (弱虫)
{55seek,{68,30}}: ambition (大志)

{36,30( indicating )}: (particular and certain) indicated time, also 'o'clock' as the standard.
Now 1-12 o'clock A.M. and 1-12 P.M. are used, but if the standard is changed, the definition
of the base overlay will follow it too. (時刻)

{37,30(show),09(affair)}: natural phenomenon (天然現象)
{30,38(make)}: instruction, instruct (vt. with ge )
{30,49(nature/quality)}: characteristic, feature, peculiarity (特徴)
{30,50(tangible thing)}: material evidence (物証)
{51(force),30}: coercion, coercive, impose (v. with gd) (威圧)
{54(existence),30}: identification( certificate) (身分証明)
{54,30}{46,28} or {54,30,46,28}: ID card
{55(request),30}: applying (to show that you want to ..) (申請)
{{55,30(indicate}(to apply),28(sheet)}: application form/card (申請書)
{56(action), 30}: demonstration (デモ)
{58(possible),30}: license/license
{60(real),30}: verification/inspection, verify/inspect (v. with gd) (検証)
{61(front),30}: appeal (n./v. with gd) (訴え)
{64(very),30}: enforced (v. enforce with ge) (強化)
{67(life),30}: symptom, phenomena of a living body (症状)

For especially computing usage with similar meanings to above(コンピュータ用の記号)

{10(place),30}: the indicated place (指示場所)
{44(open),30}: to open file (ファイルを開く)
{43(close),30}: to close file (ファイルを閉じる)
{25( + ),30}: add indications (表示増)
{04( - ),30}: reduce indications (表示減)
{07(large),30}: larger indication/icon)
{08(small),30}: smaller indication/icon )
{19(in),30}: zoom in (vt. with ge)
{20(out),30}: zoom out (vt. with ge )
{05(not), 30}: cancellation of instruction
{16(division),30}: segmentation of view (表示分割)
{28(sheet/surface),30}: screen (画面)
{28,30,07}: enlargement of the screen/canvas (画面の拡大)
{28,30,08}: reduction of the screen/canvas (画面の縮小)
{28,30,50(tool)}: monitor (visual display unit)
{15,30,28(sheet)}: file( for computing usage) (ファイル)
{15,30,{13,28}(for the shape): table( chart) (表)
{15,30,28,03(line),23(change)}: line chart (線グラフ)
{15,30,{33,07,08}(ratio; also by the shape)}: pie chart (円グラフ)
{30,31(shape)}: mark, icon, seal, signature (印章、マーク、サイン)
{46(function),30}: to show the function (機能表示)
{45(relation),30}: to show with 'thread' (スレッドの表示)

Special usage for the EL grammatical word related to the function of #30 as its single form

{30(grammatical symbol),34}: the 'an accusative case' of a verb, influenced
by the action of the subject in the EL grammar. e.g. 'it' of 'He saw it'
(The person who did the action of the verb is the subject)

Related to the shape of #30, not to its meaning (#30の形に関連)
{ga (to change the meaning of the other base overlay),30,31(shape)}: triangle (三角形)

As a part of a picture-like symbol
 `1-wW ` {02,04,30,31} as a picture-like symbol: for any kinds of shining stars in the night sky including the sun level stars, planets and galaxy.