import macros;macro ImportExpand(s:untyped):untyped = parseStmt($s[2])
{.checks: off.}
ImportExpand "cplib/tmpl/citrus.nim" <=== "when not declared CPLIB_TMPL_CITRUS:\n    const CPLIB_TMPL_CITRUS* = 1\n    {.warning[UnusedImport]: off.}\n    {.hint[XDeclaredButNotUsed]: off.}\n    import os\n    import algorithm\n    import sequtils\n    import tables\n    import macros\n    import std/math\n    import sets\n    import strutils\n    import strformat\n    import sugar\n    import streams\n    import deques\n    import bitops\n    import heapqueue\n    import options\n    import hashes\n    const MODINT998244353* = 998244353\n    const MODINT1000000007* = 1000000007\n    const INF* = 100100111\n    const INFL* = int(3300300300300300491)\n    type double* = float64\n    let readNext = iterator(getsChar: bool = false): string {.closure.} =\n        while true:\n            var si: string\n            try: si = stdin.readLine\n            except EOFError: yield \"\"\n            for s in si.split:\n                if getsChar:\n                    for i in 0..<s.len():\n                        yield s[i..i]\n                else:\n                    if s.isEmptyOrWhitespace: continue\n                    yield s\n    proc input*(t: typedesc[string]): string = readNext()\n    proc input*(t: typedesc[char]): char = readNext(true)[0]\n    proc input*(t: typedesc[int]): int = readNext().parseInt\n    proc input*(t: typedesc[float]): float = readNext().parseFloat\n    macro input*(t: typedesc, n: varargs[int]): untyped =\n        var repStr = \"\"\n        for arg in n:\n            repStr &= &\"({arg.repr}).newSeqWith \"\n        parseExpr(&\"{repStr}input({t})\")\n    macro input*(ts: varargs[auto]): untyped =\n        var tupStr = \"\"\n        for t in ts:\n            tupStr &= &\"input({t.repr}),\"\n        parseExpr(&\"({tupStr})\")\n    macro input*(n: int, ts: varargs[auto]): untyped =\n        for typ in ts:\n            if typ.typeKind != ntyAnything:\n                error(\"Expected typedesc, got \" & typ.repr, typ)\n        parseExpr(&\"({n.repr}).newSeqWith input({ts.repr})\")\n    proc `fmtprint`*(x: int or string or char or bool): string = return $x\n    proc `fmtprint`*(x: float or float32 or float64): string = return &\"{x:.16f}\"\n    proc `fmtprint`*[T](x: seq[T] or Deque[T] or HashSet[T] or set[T]): string = return x.toSeq.join(\" \")\n    proc `fmtprint`*[T, N](x: array[T, N]): string = return x.toSeq.join(\" \")\n    proc `fmtprint`*[T](x: HeapQueue[T]): string =\n        var q = x\n        while q.len != 0:\n            result &= &\"{q.pop()}\"\n            if q.len != 0: result &= \" \"\n    proc `fmtprint`*[T](x: CountTable[T]): string =\n        result = x.pairs.toSeq.mapIt(&\"{it[0]}: {it[1]}\").join(\" \")\n    proc `fmtprint`*[K, V](x: Table[K, V]): string =\n        result = x.pairs.toSeq.mapIt(&\"{it[0]}: {it[1]}\").join(\" \")\n    proc print*(prop: tuple[f: File, sepc: string, endc: string, flush: bool], args: varargs[string, `fmtprint`]) =\n        for i in 0..<len(args):\n            prop.f.write(&\"{args[i]}\")\n            if i != len(args) - 1: prop.f.write(prop.sepc) else: prop.f.write(prop.endc)\n        if prop.flush: prop.f.flushFile()\n    proc print*(args: varargs[string, `fmtprint`]) = print((f: stdout, sepc: \" \", endc: \"\\n\", flush: false), args)\n    const LOCAL_DEBUG{.booldefine.} = false\n    macro getSymbolName(x: typed): string = x.toStrLit\n    macro debug*(args: varargs[untyped]): untyped =\n        when LOCAL_DEBUG:\n            result = newNimNode(nnkStmtList, args)\n            template prop(e: string = \"\"): untyped = (f: stderr, sepc: \"\", endc: e, flush: true)\n            for i, arg in args:\n                if arg.kind == nnkStrLit:\n                    result.add(quote do: print(prop(), \"\\\"\", `arg`, \"\\\"\"))\n                else:\n                    result.add(quote do: print(prop(\": \"), getSymbolName(`arg`)))\n                    result.add(quote do: print(prop(), `arg`))\n                if i != args.len - 1: result.add(quote do: print(prop(), \", \"))\n                else: result.add(quote do: print(prop(), \"\\n\"))\n        else:\n            return (quote do: discard)\n    proc `%`*(x: SomeInteger, y: SomeInteger): int =\n        result = x mod y\n        if y > 0 and result < 0: result += y\n        if y < 0 and result > 0: result += y\n    proc `//`*(x: SomeInteger, y: SomeInteger): int =\n        result = x div y\n        if y > 0 and result * y > x: result -= 1\n        if y < 0 and result * y < x: result -= 1\n    proc `^`*(x: SomeInteger, y: SomeInteger): int = x xor y\n    proc `&`*(x: SomeInteger, y: SomeInteger): int = x and y\n    proc `|`*(x: SomeInteger, y: SomeInteger): int = x or y\n    proc `>>`*(x: SomeInteger, y: SomeInteger): int = x shr y\n    proc `<<`*(x: SomeInteger, y: SomeInteger): int = x shl y\n    proc `%=`*(x: var SomeInteger, y: SomeInteger): void = x = x % y\n    proc `//=`*(x: var SomeInteger, y: SomeInteger): void = x = x // y\n    proc `^=`*(x: var SomeInteger, y: SomeInteger): void = x = x ^ y\n    proc `&=`*(x: var SomeInteger, y: SomeInteger): void = x = x & y\n    proc `|=`*(x: var SomeInteger, y: SomeInteger): void = x = x | y\n    proc `>>=`*(x: var SomeInteger, y: SomeInteger): void = x = x >> y\n    proc `<<=`*(x: var SomeInteger, y: SomeInteger): void = x = x << y\n    proc `[]`*(x, n: int): bool = (x and (1 shl n)) != 0\n    proc `[]=`*(x: var int, n: int, i: bool) =\n        if i: x = x or (1 << n)\n        else: (if x[n]: x = x xor (1 << n))\n    proc pow*(a, n: int, m = INFL): int =\n        var\n            rev = 1\n            a = a\n            n = n\n        while n > 0:\n            if n % 2 != 0: rev = (rev * a) mod m\n            if n > 1: a = (a * a) mod m\n            n >>= 1\n        return rev\n    #[ include cplib/math/isqrt ]#\n    when not declared CPLIB_MATH_ISQRT:\n        const CPLIB_MATH_ISQRT* = 1\n        proc isqrt*(n: int): int =\n            var x = n\n            var y = (x + 1) shr 1\n            while y < x:\n                x = y\n                y = (x + n div x) shr 1\n            return x\n    proc chmax*[T](x: var T, y: T): bool {.discardable.} = (if x < y: (x = y; return true; ) return false)\n    proc chmin*[T](x: var T, y: T): bool {.discardable.} = (if x > y: (x = y; return true; ) return false)\n    proc `max=`*[T](x: var T, y: T) = x = max(x, y)\n    proc `min=`*[T](x: var T, y: T) = x = min(x, y)\n    proc at*(x: char, a = '0'): int = int(x) - int(a)\n    converter tofloat*(n: int): float = float(n)\n    proc Yes*(b: bool = true): void = print(if b: \"Yes\" else: \"No\")\n    proc No*(b: bool = true): void = Yes(not b)\n    proc YES_upper*(b: bool = true): void = print(if b: \"YES\" else: \"NO\")\n    proc NO_upper*(b: bool = true): void = Yes_upper(not b)\n    const DXY* = [(0, -1), (0, 1), (-1, 0), (1, 0)]\n    const DDXY* = [(1, -1), (1, 0), (1, 1), (0, -1), (0, 1), (-1, -1), (-1, 0), (-1, 1)]\n    macro exit*(statement: untyped): untyped = (quote do: (`statement`; quit()))\n"
ImportExpand "cplib/matrix/matops.nim" <=== "when not declared CPLIB_MATRIX_MATOPS:\n    const CPLIB_MATRIX_MATOPS* = 1\n    import sequtils\n    import strutils\n    proc rotated*[T](a: seq[seq[T]], num: int = 1): seq[seq[T]] =\n        if a.len == 0: return a\n        proc smod(n, m: int): int = (result = n mod m; if result < 0: result += m)\n        var h = a.len\n        var w = a[0].len\n        var num = smod(num, 4)\n        if num == 0: return a\n        if num == 1 or num == 3:\n            result = newSeqWith(w, newSeq[T](h))\n            for i in 0..<w:\n                for j in 0..<h:\n                    if num == 1: result[i][j] = a[h-1-j][i]\n                    else: result[i][j] = a[j][w-1-i]\n        else:\n            result = newSeqWith(h, newSeq[T](w))\n            for i in 0..<h:\n                for j in 0..<w:\n                    result[i][j] = a[h-1-i][w-1-j]\n    proc transposed*[T](a: seq[seq[T]]): seq[seq[T]] =\n        if a.len == 0: return a\n        var h = a.len\n        var w = a[0].len\n        result = newSeqWith(w, newSeq[T](h))\n        for i in 0..<w:\n            for j in 0..<h:\n                result[i][j] = a[j][i]\n    proc trimmed*[T](a: seq[seq[T]], zero: T): seq[seq[T]] =\n        result = a\n        for i in 0..<4:\n            result = result.rotated\n            while result.len > 0 and result[^1].allIt(it == zero): discard result.pop\n    proc rotated*(a: seq[string], num: int = 1): seq[string] = a.mapIt(it.toSeq).rotated(num).mapIt(it.join(\"\"))\n    proc rotate*[T](a: var seq[seq[T]], num: int = 1) = (a = rotated(a, num))\n    proc rotate*(a: var seq[string], num: int = 1) = (a = rotated(a, num))\n    proc transposed*(a: seq[string]): seq[string] = a.mapIt(it.toSeq).transposed.mapIt(it.join(\"\"))\n    proc transpose*[T](a: var seq[seq[T]]) = (a = a.transposed)\n    proc transpose*(a: var seq[string]) = (a = a.transposed)\n    proc trimmed*(a: seq[string], zero: char = '0'): seq[string] = a.mapIt(it.toSeq).trimmed(zero).mapIt(it.join(\"\"))\n    proc trim*[T](a: var seq[seq[T]], zero: T) = (a = trimmed(a, zero))\n    proc trim*(a: var seq[string], zero: char = '0') = (a = trimmed(a, zero))\n"

var h, w = input(int)
var s = input(string, h).mapIt(it.mapIt(it == '#'))

proc cnt_dp(s: seq[seq[bool]]): seq[seq[int]] =
    var h = s.len
    var w = s[0].len
    result = newSeqWith(h, newSeqWith(w, 0))
    for i in 0..<h:
        for j in 0..<w:
            if not s[i][j]: continue
            if i <= 0 or j <= 0: result[i][j] = 1
            else: result[i][j] = result[i-1][j-1] + 1

var dp = newSeqWith(h, newSeqWith(w, INFL))
block:
    for i in 0..<4:
        var dpi = cnt_dp(s.rotated(i)).rotated(-i)
        for i in 0..<h:
            for j in 0..<w:
                dp[i][j].min = dpi[i][j]
for i in 0..<h: debug(dp[i])

var imos1, imos2 = newSeqWith(h+1, newSeqWith(w+1, 0))
for i in 0..<h:
    for j in 0..<w:
        if dp[i][j] > 1:
            dp[i][j] -= 1
            imos1[i-dp[i][j]][j-dp[i][j]] += 1
            if i + dp[i][j] + 1 in 0..<h and j + dp[i][j] + 1 in 0..<w: imos1[i+dp[i][j]+1][j+dp[i][j]+1] -= 1
            imos2[i-dp[i][j]][j+dp[i][j]] += 1
            if i + dp[i][j] + 1 in 0..<h and j - dp[i][j] - 1 in 0..<w: imos2[i+dp[i][j]+1][j-dp[i][j]-1] -= 1
for i in 0..<h:
    for j in 0..<w:
        if i > 0 and j > 0: imos1[i][j] += imos1[i-1][j-1]
        if i > 0 and j < w-1: imos2[i][j] += imos2[i-1][j+1]
        if s[i][j] and imos1[i][j] == 0 and imos2[i][j] == 0: exit(No())
# for i in 0..<h+1: debug(imos1[i])
# debug("---")
# for i in 0..<h+1: debug(imos2[i])
# debug("---")
Yes()